Updated Mutation Rate Dates Make More Sense

Slowly but more or less surely, the human archeogenetics community is coming to the realization that the mutation rate used to estimate the age of various human and primate lineages was miscalibrated at a rate roughly twice as fast as it is, as we are coming to realize from a variety of new measurements of it. The dates calculated using the new calibration methods make much more sense in light of the likely archaeological corrolates of the human lineages to which dates have been assigned using mutation rate dating.

The four key points may be summarized as follows.

First, the divergence between modern humans and both Neanderthals and Denisovans, which was originally estimated to be 272,000–435,000 years ago, is revised to 400,000–600,000 years ago. This is in better agreement with the range of estimated split times from mtDNA and also with the idea that the ancestral population of these groups may have been H. heidelbergensis.

Second, for the split between the Khoe–San and other modern humans, revised estimates from nuclear genomic data suggest a divergence 250,000–300,000 years ago, older than single locus estimates for the root of the human tree.

Third, revised estimates of the separation time between Africans and non-Africans suggest that this predates the appearance of modern humans in Europe and Asia by up to 60,000 years. We have suggested a scenario of exodus from Africa via an intermediate population in East Africa and the Middle East, which may fit better with growing evidence for modern human occupation of the latter region before the wider colonization of Eurasia and may provide a longer interval for Neanderthal admixture with non-African populations.

Finally, revised split times of 40,000–80,000 years ago for Europeans and Asians agree better with the palaeoanthropological record and with estimates from mtDNA.

From here quoting Aylwyn Scally & Richard Durbin, "Revising the human mutation rate: implications for understanding human evolution," Nature Reviews Genetics, advance online publication, 11 September 2012. doi:10.1038/nrg3295.

General Analysis

The difference between the old faster mutation rate estimate and the new slower mutation rate estimate in sufficiently great to make essentially every historically interesting hypothesis conclusion reached with the old dates invalid. The implausibility of the old dates is one of the reasons that people who have looked at the old estimates from an interdisciplinary perspective, myself included, have long been skeptical of them, even before direct evidence that the slower mutation rate estimate was more accurate emerged.

The new dates for Neanderthal divergence from modern humans, for the appearance of anatomically modern humans, for Out of Africa, and for a staged migration scenario that causes the West Eurasian-East Eurasian divide within non-Africans to occur much later than the African-non-African divide all make much more sense with the slower automsomal mutation rate than the old dates. With the new calibrations, other dates estimated via mutation rates for which we don't have archaeological data to calibrate against may also become more credible.

The fact that is possible to come up with a calibration of mutation rate dates that coroborates the archaeological data and has internal coherence is also a relief. It had looked possible in the last year or two that meaningful absolute dating based on mutation rates might simply be impossible, because the assumption that there was a stable genetic mutation rate in humans that could be applied across the nuclear genome might have been fundamentallly flawed. If this was the case, the population genetic contribution to discerning the course of prehistory in a scientifically reliable way could have been virtually destroyed. This fear increasingly looks unfounded, at least outside areas of the genome where neutral genetic drift rather than strong natural selection. Some parts of the non-recombining Y-DNA genome may remain particularly problematic due to strong selective effects, and cofounding instances of introgression of multiple populations that make populations look older than they actually are may also continue to be an issue, however.

Analysis of Discrepency In The New Dates

The archaeological date typically cited for the appearance of anatomically modern humans in Africa is around 230,000 to 250,000 years ago, both the genetic and the archaeological dates have a margin of error, and the archaeological dates are always subject to significant adjustment if a new, older archaeological find is found and reliably dated. The archaeological date is the latest possible date at which anatomically modern humans could have arisen. The archaeological record of hominin remains generally that are that old is quite thin in the period from, for example, 200,000 years ago until 350,000 years ago, and the total number of anatomically modern humans alive at first would have been very small, so it wouldn't be very surprising at all for an accurate date for the origin of modern humans to have a genetic date to be a bit older than the oldest discovered anatomoically modern human remains. So, the Khoe-San divergence date cited isn't far off from the likely point of origin of modern humans in the archaeological record.

The possibility that the most recent common ancestor of modern humans as determined by non-recombining Y-DNA genetics and mitochondrial genetics could be younger than the date determined by autosomal genetics isn't necessarily very troubling either.

As the presence of Neanderthal and Denisovian autosomal genetic contributions in the human genome despite the absence of any Y-DNA or mtDNA traces of this admixture (or archaic African admixture that indirect methods suggest is found in Paleo-African populations at a fraction lower than that of Neanderthal admixture in non-Africas), all uniparental genetic traces of an introgressing population can be lost yet still leave autosomal genetic traces.

There are some very specific considerations that apply to the purging of uniparental mutations in the case of archaic hominin admixture that I have discussed in previous posts and that may not apply to early anatomically modern humans pre-Out of Africa. In general, low frequency uniparental gene in a population are unlikely to drop out of the gene pool during periods when a population is expanding, but do drop out of the gene pool with some frequency when the size of the population is small and stable, fluctuates up and down multiple times, or when it is getting smaller due to a population bottleneck. Some of these conditions were probably present for some of the period betweeen the evolution of the earliest modern humans and the Out of Africa date, so it wouldn't be surprising if age of the most recent common Y-DNA or mtDNA ancestor of modern humans is at least somewhat less than that of the same date determined looking at the richer set of automomal genetic data.

Could Population Structure And Admixture Explain Automsomal Genetic Ages Much Older Than Uniparental Genetic Ages?

If I recall correctly, uniparental mutation rate dating has pointed to a Paleo-African divergence from other modern humans more or less around the time of the Out of Africa event when consistent dating methods are used to fix both dates (ca. 60,000-70,000 years ago in the old calibration and closer to 100,000-140,000 years ago with the newly calibrated dates, if my memory served me). Uniparental phylogenies of non-recombining Y-DNA and mtDNA have also implied that the Khoe-San and Pygmies may share a common ancestor distinct from other modern humans at this point.

This is a big discrepency with the 250,000-300,000 year old date above, which may be hard to fit to a model of uniparental haplogroup purging solely due to random genetic drift. This is no genetic evidence so far for a modern human population bottleneck in Africa itself in early human prehistory, slow population size growth in Africa over these many tens of thousands of years is a plausible demographic scenario used in most population genetic models with success, and estimates of African effective population sizes are generally greater than estimates of non-African founding population effective population sizes.

But, admixture of diverse populations can make the automsomal genetic of the population look older. The same effect, by the way, is also seen when one estimates the time of emergence of two languages from each other based on lexical data, that is quite visible in recent efforts to date Indo-European linguistic origins on this basis.

It also seems unlikely, however that the modest amount of archaic admixture inferred to be present in modern Paleo-African populations is enough to give rise to this discrepency. There simply isn't enough of inferred archaic admixture in these populations (we have no ancient DNA from Africa which we can use to test the hypothesis directly as we do with Neanderthals and Denisovans). While Dienekes' has suspected that admixture with archaic hominins may be producing an artificially old autosomal estimate for Paleo-African population divergence, my own intuition is that admixture of diverse modern human African populations, some of which no longer have unadmixed survivors, seems like a more likely variant of this hypothesis.

A Plausible Admixture Scenario That Could Explain The Discrepency

Consider the following scenario that could explain why Paleo-African populations look older from an autosomal genetic perpsective, dating to around the time that modern human arise, than the apparent date of their divergence from other modern humans based on mutations in their uniparental genetics.

Suppose that anatomically modern humans began to fracture into diverse and geographically structured populations within Africa, with limited admixture with populations other than ones immediately bordering them, almost immediately upon evolving from one of the Homo heidelbergensis hominin species branches around 250,000-300,000 years ago.

Suppose also that anatomically modern humans did not admix with peoples other than anatomically modern humans after the emergence of this new species, except for a few clearly defined episodes of admixture with archaic hominins. Specifically, Neanderthal and Denisovian admixture outside Africa, and one or two smaller episodes of admixture with archaic hominins with Paleo-Africans within Africa where larger effective population sizes of anatomically modern humans may have reduced the impact of archaic hominin introgression.

Suppose that some of the "first wave" Paleo-African populations that began to diverge immediately from a core single modern human population near where anatomically modern humans evolved in the first place, probably somewhere in East Africa, which was more or less homogeneous genetically. There would have been many smaller first wave Paleo-African populations at diverse locations elsewhere in Africa, most of which were less successful because they had not evolved as specifically to be adapted to the conditions elsewhere in Africa.

Suppose that the core of extant Paleo-African populations in Africa are traceable not to this first wave of Paleo-Africans, but to a second wave of hunter-gatherers that split off from the core East African hunter-gatherer population much later. This second wave of Paleo-Africans would have evolved genetically and culturally in a way that made them more fit than first wave Paleo-Africans in environments less like the one that modern humans had originally evolved in, in other words, generalist advantages. These adaptations, present in non-Africans and second wave Paleo-Africans, but not in archaic hominins and first wave Paleo-Africans, gave the second wave Paleo-Africans a selective advantage over the existing "fringe" hominin populations of Africa and over archaic hominin populations outside Africa.

The remnants of first wave Paleo-African may have eventually been absorbed as minor components of other African populations. In extant Paleo-African populations, genetic drift could have eliminated uniparental markers of the existence other Paleo-African populations at the fringe of the pre-Out of Africa modern human world, while still leaving enough of an autosomal genetic impact on populations of extant mostly "second wave" Paleo-African populations to make the autosomal genomes of extant Paleo-Africans look older than the point in time at which the bulk of their ancestors diverged from a modern human core population in Africa. But, any automsomal contribution from introgression of "first wave" Paleo-African populations into the core modern human population in Africa, if there was one, may have been too slight to be detectable in the genomes of populations derived from this core modern human African population because it was larger relative to the introgressing first wave Paleo-Africans.

A Brief History of Prehistoric Europe

Preface

A rush of new abstracts of genetics papers were released last week at a major academic conference, and before posting about them, it is really time to take a step back and recap the broad outlines of what we believe we know about prehistoric Europe to put those discoveries in a context in which the papers, which often make predictions based on modern and/or ancient populations genetics about the timing of the geographic and demographic expansions of historical linguistic proto-populations.

In my view, these new genetic data points must ultimately be fit to the more concrete, more direct and more accurately dated and characterized archaeological evidence of radiographically and deposit stratum dates relics and remains.

This post  outlines the history of prehistoric West Eurasia with a particular eye towards the phenomena of Indo-European language expansion prior to the Medieveal period. Ultimately, this post concludes when the main subfamilies of the Indo-European languages in Europe and South Asia are in place sometime in the Iron Age, with some footnotes on some of the later linguistic developments in Europe.

Very little of Europe was part of the Indo-European language family at the dawn of the Bronze Age, but by the end of the Iron Age that followed, the Indo-European language family had experienced most of its ultimate expansion in geographic range.  It has also exterminated almost all of Europe's other languages as well as many relatively basal branches of the Indo-European language family itself in Europe.  Most of the later expansions and migrations of Indo-European language speaking peoples, prior to the era of European colonial empires, would be into areas where other Indo-European languages were already spoken.

Twenty-five centuries later after the Indo-European languages began to experience this massive expansion, the only non-Indo-European languages left in Europe by the end of the first century of the current era (i.e. AD aka CE) at the height of the Roman Empire were Basque (in Northern Spain and Southwestern France), the Finno-Uralic languages of Finland and other parts of far Northeastern Europe and North Central Asia, and the various language families of the Caucasus Mountains that form one of the boundaries between Europe and Asia (together with the Ural Mountains, and various bodies of water).  All other non-Indo-European languages now spoken in Europe arrived in the Medieval period.

Almost all of the non-Indo-European and non-Semitic languages of Western Asia were also extinct by then.  The Sumerian language of Mesopotamia, the language of the Harappans, and all of the ever attested non-Indo-European languages of Anatolia and the Zargos Mountains such as Hattic, Hurrian, Kassite, Elamite, and at least one other lost non-Indo-European language family spoken between the Kassite and Elamite linguistic regions in the Zargos Mountains were extinct or moribund by then.

The non-Latin Celtic and Italic languages of Continental Europe were extinct or moribund, although some of the Celtic languages lived on in the British Isles.  The Anatolian languages were also all extinct or moribund by then, as were many of the Indo-European Aegean languages.

This post fits known archaeological cultures whose ages and geographic extend are largely established to particular hypothesized language family affiliations. This post states what is my most likely hypothesis without spelling out in detail the degree of uncertainty with each component of the hypothesis.  But, some of the points are definitely less certain than others.  The short sketch of the Indo-European speaking people's expansion in time and space from a proto-language that I have provided starts with the language spoken by the Yamna people on the Pontic steppe, arguably the last point in time at during which there was a single proto-Indo-European languages spoken in a geographically compact area.  This analysis largely tracks the leading Kurgan hypothesis regarding this process.

An Big Picture Outline of The Main Eras Of Early European Prehistory

The Paleolithic Era

The first hominins to leave Africa, Homo Erectus, evolved in Africa around 2 million years ago and had spread as far as the island of Java in Indonesia by about 1,800,000 years ago.

Neanderthals, the prior hominin residents of Europe and West Asia became distinct from earlier hominins in Europe or Africa around 500,000 to 750,000 years ago.  Neanderthals probably share a branch of the tree of life of the genus homo called Homo Heidelbergus with modern humans that originated in Europe or Africa that broke away from Homo Erectus after Homo Erectus left Africa.  Neanderthals had a range that included all but the coldest parts of Europe, Pakistan, some of India and Central Asia.  It isn't entirely clear to what extent Neanderthals were present in high alpine environments.

Archaeological evidence from the interior of Arabia and Israel place the earliest modern humans to leave Africa, who are the primary source of genetic ancestry for all people who lack African descent in the last five hundred years or so, starting around 100,000 to 125,000 years ago from a population whose civilization in called the Nuba complex in the Nile River Basin until about 80,000 to 75,000 years ago, after which there was a roughly twenty-five thousand year long period of discontinuity in the places where remains of anatomically modern humans first left Africa.  Most modern human Neanderthal admixture today in non-Africans appears to have its origins in this era of non-African prehistory rather than the thousands of years of co-existence in rough geographical proximity to each other that followed.

The reappearance of signs that modern humans lived there again around 50,000 years ago.  In the interim, they spread out of Arabia to destinations including the highlands of West Asia (somewhere), possibly interior oasises in Arabia or the Persian Gulf, and India. 

Neanderthals decline in population in Europe close in time to the arrival of modern humans and some major volcanic eruptions in Europe, and may have declined in population of gone extinct in West Asia and South Asia sooner than then.  Anatomically modern humans called Cro-Magnons arrive in Europe in an era called the Upper Paleolithic which commences in Europe about 43,000 years ago, give or take.  But, Neanderthals do not go extinct entirely in the last caves where their remains have been discovered until around 28,000 years ago.

Before they go extinct, Neanderthals provide via admixture about 10% to the autosomal genome of Cro-Magnon hunter-gatherers in Europe (compared to something like 3% in modern Europeans), but subsequent migrations from areas that had far less Neanderthal admixture ultimately dilute this elevated contribution to barely distinguishable levels.  Some remains show signs that later Neanderthals had visible modern human admixture as well and this may have been what gave rise to many thousands of years that marked the first period during which there had been major advances in Neanderthal material culture since they established their signature Mousterian set of stone tools hundreds of thousands of years earlier.

Northern Europe and Siberia are completely depopulated during the Last Glacial Maxmium ca. 20,000 years ago, and is repopulated from the South, in part from a Franco-Cantabrian refugium, from the Italian Peninsula and a Southeastern European refugium starting around 16,000 years ago. The period of the repopulation of Europe, or at least the last few thousand years of it, starting around 12,000 years ago (two thousand years before the Fertile Crescent Neolithic revolution) is called the Epipaleolithic era and is a time of considerable West Asian/Southwest Asian migration into Southern Europe and Northern Africa.

The Neolithic Revolution 

The Neolithic Revolution that commences the Neolithic era is marked by replacement of hunting and gathering modes of food production with farming and herding. In the Fertile Crescent (including the Levant, Anatolia and Mesopotamia), and probably some adjacent areas, there are multiple stages of the Pre-Pottery Neolithic era, but pottery is part of the Neolithic culture by the time it spreads very far into Europe, moving beyond the far Southeastern corner of Europe, mostly in connection with two first wave Neolithic cultures, the Linear Pottery Neolithic (more or less making its way up the Danube River) in the East and the Cardial Pottery Neolithic which makes its way across Southern Europe in the East.  These two waves of migrants, who bring about the Neolithic transition more by migration of entire peoples than by cultural transmission to pre-existing hunter-gather populations.

The early Neolithic era originates in the Fertile Crescent around 8000 BCE (10,000 years ago, aka the start of the Holocene era).  Around a thousand years later, around 7000 BCE, and also about a thousand years before the Neolithic culture spreads into Europe via the Fertile Crescent Neolithic had already spread to the Indus River Valley and the Nile River basin in Europe around 7000 BCE. 

The commencement of the Neolithic era varies from place to place in Europe (from roughly 6000 BCE in the Balkans to 3500 BCE in Scandinavia).

The Atlantic megalithic culture emerged from the Cardial Pottery first wave Neolithic people of Southern Europe.  They may spoken languages that were part of the same linguistic family as Etruscan and the contemporaneous and related Alpine Rhaetic language (not to be confused with the modern Rhaetic language of Switzerland which is Indo-European). The Rhaetic and Etruscan people, in my opinion, most likely had their origins in Southern French Cardial Pottery wave peoples until incoming Urnfield people or Celts drove them out in the Iron Age. The Cardial Pottery people, in turn, had origins in the general vicinity of the Aegean and Anatolia at the dawn on the European Neolithic.

The Cardial Pottery Neolithic migration from which emerged the Atlantic Megalithic people and the next wave Vasconic Bell Beaker peoples, combined, mostly replaced local Mesolithic people, at least in the Southern part of the Bell Beaker area, from a population genetic perspective.

The Copper Age

In Western Eurasia, recognizable civilization begins in the Copper Age, which follows the early Neolithic era, starting around the last half of the 3000s BCE, and ends when the Bronze Age begins, about a thousand years later.  There are places in the Northern fringes of Europe where the arrival of the earliest farming and herding peoples sometimes called the arrival of the Neolithic people in the region, actually involved Copper Age people rather than true early Neolithic populations. 

The Copper Age is when the first cities appear and the Sumerians and Egyptians independently invent writing, as well as the earliest widespread manufacturing of metal. It may also coincide with important, but somewhat obscure, advances in herding and farming technologies including the increased importance of milking cows as a part of people's diet in Europe.

The Minoan Palace civilization in Crete, the Sumerian city-state federation's cultural zenith in Mesopotamia, the pinnacle of the Harappan civilization in the Indus River Valley, and the first historically attested dynasties of ancient, pyramid building, hieroglyphic using, Coptic language speaking Egypt date to the Copper Age.  Some of the Biblical book of Genesis (e.g. at least some of the story of the Creation, the Garden of Eden, the Tower of Babel, and Noah's flood) and the birth story of Moses in the Biblical book of Exodus, clearly draw on Sumerian legends from the Copper Age.

Horses were domesticated in the European Steppe and wheeled vehicles were invented around 3500 BCE, close in time to the start of the Copper Age.

The Bell Beaker culture starts its expansion into Western Europe in the Copper Age.  The Copper Age to Bronze Age Bell Beaker culture was in my best estimate, a non-Indo-European, probably proto-Vasconic (i.e. Basque linguistic family) superstrate imposed on a linguistically non-Indo-European Neolithic Atlantic Megalithic culture substrate that spoke languages in a single language family that were not part of either the Indo-European or Vasconic language families, probably the language derived from the original Cardial Ware pottery Neolithic migrants.

The Pit Comb Ware aka Comb Ceramic culture starts about 3200 BCE and continues until the mid-Bronze Age.  It was linguistically Uralic, is derived from further East in Northern Asia, and is probably the main genetic source for the East Eurasian affinities seen in Northern European autosomal genetics and in uniparental haplogroups like N1a which are seen in Northern Europeans.

The megalithic Funnelbeaker (TRB) people were a declining phase of the LBK Neolithic wave migrants under pressure from both the hunter-gatherer Pit Ware peoples and the emerging Indo-European people who were their neighbors. The pressure from the Indo-Europeans reaches a tipping point around 2900BCE-2400BCE when Indo-Europeans gains a decisive edge over TRB people for some reason. The TRB culture is probably where most of the admixture of Mesolithic hunter-gatherer people and first wave Neolithic people revealed by modern Northern European population genetics took place.  The Funnelbeaker culture is noted archaeologically for showing signs of admixture between hunter-gatherer peoples and the successors to the LBK farmers, probably as a result of declining climate conditions for farming causing hunting and gathering and farming to reach a point of rough economic prestige equity.

Indo-European languages are present only in a proto-Indo-European (PIE) Yamna culture limited to the Pontic steppe (basically, the Ukraine) until the dawn of the Bronze Age, with perhaps a small proto-Tocharian group leaving around 3500 BCE to make a long journal across the Russian steppe via intermediate settlements who arrive in Tarim Basin ca. 2000 BCE, and a proto-Corded Ware culture group that arrives in Poland around 3000 BCE. The current theory is that the Proto-Indo-Europeans of the Yamna culture were mostly nomadic herders who had a minor involvement in farming, but this remains a controversial point.

The Bronze Age

The Bronze Age starts sometime in the mid-2000s BCE and ends with "Bronze Age collapse" around 1200 BCE.  It is associated among other things with the widespread use of Bronze metals (an alloy of copper and zinc from which is more suitable than pure copper in many applications).  The Bronze Age is a period of legendary history in Europe full of heroes, demigods, epic battles, empire builders, warriors, revenge, and explorers, in which it is hard to separate fact from fiction. It is the setting for most Classical Greco-Roman mythology, for most Norse mythology, for most Hindu mythology, for most Greek mythology and for numerous Egyptian legends.

This is the era when chariot warfare became widespread from Egypt to Central Europe to Iran to India, mostly from driven by warriors in expanding linguistically Indo-European populations, and by the peoples reacting to encounters with them.

As set forth below, it was also a period of massive expansions and conquests for two societies in Western Eurasia historically made up of nomadic herders, the Semites and the Indo-Europeans. 

While I don't emphasize the point here given the expressly West Eurasian focus of this post, it is likely although not certain, that the Bronze Age technological package was exported, mostly culturally rather than demically, via the Silk Road from the Pontic Steppe to Northern Asia, triggering the emergence of Bronze Age societies in China and its vicinity with a distinctly Asian character.  Ultimately, these developments may have made possible later expansions across Northern Asia and into West Eurasia of first the Turks and later the Mongols in the first fifteen decades of the current era.

*** A Footnote On Armenian

I discuss the expansions of all of the major branches of the Indo-European languages during the Bronze Age here except Armenian which has a small current geographic scope, a modern population history from the Armenian genocide not reflected in its current geographic distribution, a complex set of areal influences from other Indo-European languages that is reflected in its varied isoglosses, a historically ill established origin until the Middle Ages, and a possible origin in the Aegean or Eastern Turkey followed by a long distance migration.  This is too much to fit into a "brief" one post history of prehistoric Europe.

*** Bronze Age Semites

A historically documented drought in Mesopotamia at this time finished off the linguistically Sumerian civilization of Mesopotamia (which was replaced by the Semitic Akkadian language except for religious purposes) and this is probably the time period when the Semitic taboo against eating pork shared by Jews and Muslims today arose.

The Bronze Age definitely preceded Islamic ethnogenesis (which required the prophet Muhammad to deliver his revelations in the 7th century CE), and probably also preceded Jewish ethnogenesis, as distinct from a merely generalized Semitic ethnic identity. The Semitic Mediterranean maritime trading civilization called the Phoenicians emerged in the late Bronze Age and continued to remain vital through the subsequent Iron Age.

This event lead to the first "intermediate period" in the written history of dynastic Egypt, during which Semitic Hyskos people ruled Egypt. The early Bronze Age was also probably roughly the time that the speakers of the Ethio-Semitic proto-language arrived in Ethiopia, had a meaningful male biased genetic impact, and probably replaced the existing Afro-Asiatic languages from the Cushitic language family.

*** Bronze Age Indo-European Indo-Aryan Expansions

The severe climate events at the start of the Bronze Age reroute the course of the Saravasti River (between the modern Indus and Ganges Rivers of South Asia) which is a key geographic feature in the proto-Hindu Rig Vedas, thereby destroying much of the Harappan civilization of the Indus River Valley that had been built up on its banks.  Indo-Aryans arrive in South Asia about 2000 BCE with room to be a up to few hundred years older (before which Harappan cultural traces preclude earlier dates) if new archaeological discoveries find something a bit older.  The main expansion into the Indian Peninsula continues over a few hundred years to include all of the areas where Indo-Aryan languages derived from their original language, Sanskrit, in which the Rig Vedas, which probably started to be composed around 2000 BCE, are spoken today in South Asia (of which Hindi is the most widely spoken) linguistically.  Religiously all of India's Dravidian language speaking areas as well. 

In the late Bronze Age around around 1500 BCE, the Mittani Empire in the Zargos Mountains of Iran and Northern Mesoptomia was ruled by a Sanskrit speaking elite (rather than the proto-Persian language speaking ruling class one might expect) who ruled over a mostly non-Indo-European Kassite language speaking population and are remembers most for their equestrian manuals which survive to this day in Hittite translation that preserved many of the original Sanskrit derived technical terms.

Genetic traces of the Indo-Aryan superstate dated with genetic evidence to roughly the right historical time period for the arrival of the Indo-Aryans documented by other means are generally much stronger in high caste Indians in general, than in lower caste Indians.  They Indo-Aryans may have invented the caste system, but could also have simply placed themselves in their own caste or a previously much smaller caste at the top of a pre-existing caste system.  Indo-Aryan genetic influences is somewhat difficult to parse because it is superimposed on a pre-existing genetic divided between Ancestral North Indians and Ancestral South Indians that probably predates the Indo-Aryan invasion by at least five thousand years when the Indus River Valley civilization was established by Fertile Crescent Neolithic culture migrants and perhaps even further back into the Paleolithic era.

*** Expansion Of Other Bronze Age Indo-Iranian Populations

The larger Indo-Iranian language macrofamily within the Indo-European language family includes not only Sanskrit derived Indo-Aryan languages, but also most of the languages of modern Iran (including Persian) and most of the languages of modern Afghanistan.  The origins of the Indo-Iranian languages are probably a century or three earlier than the origins of the Sanskrit branch that gave rise to the languages of India a bit closer to Central India than the Cemetery H in Northeast India which is the oldest reliably dated, culturally Indo-Aryan site. 

One possible place of origin for Indo-Iranian society could have been in the conquest of the BMAC archaeological complex of Central Asia, which was the furthest flung colony in the Harappan sphere of influence, allowing them to absorb cultural influences that nomadic herders of Central Asia couldn't have acquired otherwise such as irrigated agriculture concepts.  There are aspects of Zoroastrian religion that seems to parallel BMAC religious ideas.

From the Bronze Age until the arrival of Turkic warriors on horses in the first millenium of the current era (for example, the original Huns and in time the Turks who became as superstate population in Anatolia and gave it the Turkish language spoken there today), the languages of Central Asia's herders were Indo-Iranian ones, like Scythian.

An early form of the Persian language was the language of the proto-Zoroastrian Persian religious text called the Avesta, which was composed in the late Bronze Age, around 1500 BCE and is the main intellectual source for the stark religious good-evil duality with God and the Angels in Heaven fighting for good against Satan and his demons in Hell fighting for evil that emerges within Judaism during the intertestamentary period and makes its way into early Christian theology and metaphysics. This probably derived as a result contacts with Zoroastrian ideas during an intertestamentary period of exile to Mesopotamia and was also found in other Jewish sects during the formative period of early Christianity. This kind of dualism was not a part of Hebrew Bible era Judaism in the same way. The recent fantasy movie "Prince of Persia" is set in Bronze Age Iran.

Evidence of non-Indo-European languages including Elamite and a previously unknown language of people from the Zargos mountains, suggest that the Indo-Iranian linguistic monopoly in Iran may have come much later to Southern Iran than had been previously assumed.

One of the confounding issues in historical Indo-European linguistics has been the inability of linguists to meaningfully characterize substrate influences for the Indo-Aryan or other Indo-Iranian languages, nor is there the legendary tradition of migration into the region found in most other Indo-European societies.  This confounding question is accompanied by other ones.  What historical language could have been a source for or influence on Proto-Indo-European as spoken by the Yamna people?  How did the nomadic herders of the Pontic-Caspian steppe develop such an advanced agricultural and metallurgical vocabulary?  What is the cause that drove the sudden expansion of Indo-European languages somewhat before the beginning of the Bronze Age wrecked havoc in Mesopotamia and the Levant?  If horses and the wheel were really important to Indo-European expansion, why was most of the expansion delayed for another thousand years after these technologies were developed by the Indo-Europeans?

Given that the Proto-Indo-European culture was near the fringe of the expansive Harappan empire's advanced civilization, as well as the advanced metallurgy of the Caucasian civilizations of the time, one possibility is that a Harappan cultural infusion to Proto-Indo-European society, fueled by desperate exiles from a rapidly collapsing civilization built around millenia of warless stability and intruding into their territory in search of new homelands, provided an infusion of cultural material that when melded with an otherwise not particularly exceptional Yamna culture created the right combination to gain a decisive advantage over their neighbors.

*** Bronze Age Indo-European Hittite Expansions

It was in the Bronze Age that the Indo-European Hittites, starting with just a two city kingdom, built the first historically attested empire to include all of Anatolia and some of Northern Mesopotamia and the Northern Levant.  The zone of Hittite control extended all of the way to the Levantine northern border of Egyptian control in the vicinity of modern Lebanon.  This was the furthest South that any linguistically Indo-European empire would extend until the Roman empire came to rule the North African coast.  The Hittites and Egyptians fought chariot battles with each other and exchanged royal brides to make alliances.

Hittite expansion which is fairly well documented in Akkadian and Hittite documents (impressed in clay and first written by Mesopotamian traders at frontier trading posts) and also fairly well documented archaeologically, starts in the Bronze Age in Anatolia at about 2000 BCE and leads to the end of Hattic languages.

There is not bona fide dispute over when the Anatolian Indo-European languages became the overwhelmingly dominant language family in Anatolia, even if there is dispute over the pre-Hittite language mix in Anatolia with some arguing for an Indo-European proto-language origin in pockets of Anatolia that were not Hattic or Hurrian, rather than a proto-language origin with the Yamna culture on the other side of the Black Sea from Anatolia that extended to Anatolia's fringes on both the East and West.

The highly divergent character of Anatolian languages in the Indo-European language family has more to do with the great differences between the non-Indo-European language family substrates in Europe and the non-Indo-European language substrates in Anatolia, than it does with its great antiquity or particularly basal position in the Indo-European linguistic tree.

*** Bronze Age Indo-European Expansions Into Greece.

In what is now Greece, in the early Bronze Age, probably also around 2000 BCE, Indo-European Proto-Mycenaean Greek replaces first the non-Indo-European mainland pre-Greek language from the North or Northeast, and then from there goes on to replace the non-Indo-European Minoan language (both mainland pre-Greek and Minoan were probably part of the same non-Indo-European language family). Mycenaean Greek like the Anatolian languages, shows considerable influence from its substrate. Both of these substrate languages may well have been part of the same linguistic family as Hattic.

*** Bronze Age Indo-European Germanic Expansions.

It was in the Bronze Age that a proto-Germanic language was probably first spoken across a region including most of modern Germany and Poland, replacing some now lost non-Indo-European languages, some of which probably part of the same linguistic family as the modern Finnish and Uralic languages.  Other languages lost in the expansion of the proto-Germans would have been the languages in the linguistic family of the first European farmers in the region, the Linear Pottery Culture farmers, who arrived via Southeastern Europe, probably from Anatolia or the Caucusas across Balkans to the Danube and tracing this river and its tributaries into Europe.

The Corded Ware culture was a linguistically Indo-European population that dates from ca. 3000 BCE (at the earliest Polish sites) to 2400 BCE at its greatest extent in Western Germany, generally moving from East to West over that time period during the Copper Age to Bronze age transition with the geographic gains weighted towards the tail end of that period. The Corded Ware culture's language was probably either proto-Germanic and the main substrate language in proto-Germanic.

*** Bronze Age Indo-European Tocharian Expansions.

It was in the Bronze Age that the linguistically Indo-European and racially Caucasian people of the Tarim Basin, called the Tocharians established themselves there after migrating from their settlement to the North (around 2000 BCE) and then continued their civilization until well into the Iron Age.  Their civilization would last uninterrupted at this last West Eurasian stop on the Silk Road because East Eurasian lands began for about two and a half thousand years, before being lost to history until the 20th century of the current era.

Since the Tocharians appear to have broken off from the Yamna culture proto-Indo-Europeans earlier than any of the other Indo-European branches and unlike other Indo-European migrants moved into essentially unsettled territory where there were no substrate influences of any kind, their branch of the Indo-European linguistic family tree was probably the most conservative of the original proto-Indo-European language.

*** Bronze Age Collapse.

Bronze Age collapse is associated with the demise of the Hittite Empire in Anatolia, the Trojan War, an "intermediate period" in Egypt, the arrival by boat of the Mycenaean Greek Philistine people referred to in the Bible in the Southern Levant, and the collapse of the pre-Indo-European Atlantic megalithic culture as transformed by the subsequent Bell Beaker culture.  Both its beginning and its end are punctuated by severe extended droughts in the Fertile Crescent region and areas adjacent to it. 

The Iron Age

Bronze Age collapse is followed by the Iron Age which extends at least until, and arguably includes the Classical Greek and Roman civilizations.  Iron implements, which were rare and valuable prior to the Iron Age whose workings were closely held secrets, became ubiquitous after Bronze Age collapse when the secrets of working it and mining finally it got out.  Iron is actually in many ways inferior to Bronze in the applications to which it was put, but was much more amenable to being cheaply mass produced to outfit large armies with metal weapons and armor.

The tail end of the Biblical book of Genesis, the Biblical book of Exodus and the rest of the Hebrew Bible appear from their references to peoples, places and regimes, to be set in a period during or after Bronze Age collapse.

The Celtic and Italic wave probably have its origins in the Urnfield culture which moves from Central Europe into Italy and Western Europe starting around 1300 BCE in the late Bronze Age, and these languages expand into the various Indo-European languages of Italy and Western Europe.  The Italic languages survive today largely via the Romance languages (French, Spanish, Italian, Portuguese, Romanian, etc.) which themselves are remnants of the disintegration of the common Latin language of the Roman empire falling the Western Roman Empire's collapse.  Rome was established some time in the early Iron Age.

Slavic expansion comes much later, not earlier than 200 CE and probably more like the 6th century CE.  This expansion erases most linguistic clues about earlier language in the Slavic region.

The Medieval Period and Beyond

The period after the fall of the Western Roman Empire, around 430 CE, is normally called the Medieval period.

This characterization as an in between period in history makes less sense, however, when describing the late Byzantine Empire (previously the Eastern Roman Empire, which was much more densely populated and affluent, where Greek rather than Latin was the primary language) which didn't experience the defining moment that commenced the Dark Ages, the rise of Islam and expansion of the Islamic empire starting in the 7th century CE which gave rise to a Golden Age of Islam at the intellectual center of the world, and the successor states to the early Islamic empire in the European Medieval period, and moved onto a really new era only much later than the Italian Renaissance.

The non-Indo-European languages of Europe other than Basque and the Finno-Urgric languages of Northeastern Europe which are not attributable to European colonial era immigration to Europe or subsequent immigration to Europe, were established in Europe in the Medieval period. They are Hungarian (Uralic family), Turkish (Turkic family), Hebrew (Semitic family), Maltese (Semitic), and Yiddish (a Hebrew-German creole). In addition, the Indo-European Slavic languages reach their present extent in Europe, and Latin differentiates into the modern Romance languages, only after Rome falls. 

A recent genetic study suggests that all Ashkenazi Jews derive from an effective population of about 400 people around the time of the Crusades which was also the time of the first post-Roman pogroms and exiles, many of which were very extreme.  For example, Jews were expelled from Britain and any Jews who remained were forced to do so in secrets that were well kept from history as well, for approximately four hundred years after being common place almost all of the major cities across Britain before then. 

European historians call the era starting around 1500 CE in with the Renaissance, and continuing up to the present, the "modern" era.

Sun Exposure Drives Apparent Gamma Decay Rate

Radioactive isotypes of atoms naturally experience alpha, beta and gamma decay at particular characteristic rates tied to fundamental laws of physics and the structure of very large atomic nuclei.

Detectors that try to measure gamma decay rates show seasonal and daily variation matching differences in the angle with which the suns rays hit the laboratory site.

Lubos Motl, correctly in my view, reasons that the variations in gamma decay rates observed by the detectors don't actually involve seasonal and daily shifts in gamma decay rates. Instead, he reasons, seasonal and daily variation probably actually involve collisions between something emitted by the sun and the radioactive materials that varies with the directness of angular exposure to the sun, that merely looks like gamma decay to the detector, when it is in fact something entirely different.

The thing that is triggering the collisions could be (1) photons (of wavelengths that can penetrate the materials containing the radioactive isotypes, or that trigger collisions outside the containing materials that in turn generate secondary effects that reach the detectors), (2) neutrinos (which he disfavors on the theory that neutrinos would disproportionately influence beta rather than gamma decay, which is a neutrino generating process), or (3) something else emitted by the sun.  Neutrinos also ought to have peaks twice a day, rather than once, because the Earth provides little shielding from them since they are so unreactive, and so should peak when the sun is mostly directly above and below the experiment, rather than merely once a day as shown.

The finding matters not just because a previously unknown source of collisions related to sun exposure was discovered, but also because the study suggests that prior measurements of gamma decay rates that don't account for the influence of sun exposure and simply rely on average gamma decay rates, systemically overestimate true gamma decay rates due to false positives from sun exposure correlated collisions.  Without this correction, we might misinterpret future deep space experiments measuring gamma decay rates that lack this sun exposure induced collision effect.  The systemic error of experiments that don't account for this factor could even lead to incorrect parameter estimation of Standard Model constants that give rise to gamma decay, although most of these parameters are estimated are far "cleaner" experiments than the decay of large radioactive isotypes.

The results may very well be the source of "new physics", but probably not new "fundamental physics."  Instead, it may help us better understand what the sun emits and at what energies and how those emitted products interact with the kind of materials found in radioactive decay measurement laboratories.  This may tell us more about the complex structure of a fairly typical star, but doesn't tell us much about the fundamental physics of radioactive decay, other than to use trough rather than average values for many purposes.

Religion And Food Production

Consider the following conjecture.

For any given technological tool kit and ecological niche there are favored approaches to producing food and more generally overall basic form of economic organization.  Some of the medium grained possibilities (between coarse grained and fine grained) might be terrestrial hunting and gathering, fishing, herding, hoe based farming, plough based farming, irrigation based farming, raiding, mechanized farming and industrial production, post-industrial economic organization.

For any of these modes of food production (although types of basic economic organization might be a more accurate terminology), there is a particular set of values, cultural norms, modes of collective organization, scale of collective organization and type of political culture that is favored.  The values and social organization that works for a herder is to a great extent determined by this mode of food production and is something along the lines of a "culture of honor."  Plough based farming may favor patriachal societies, while hoe based farming may not have that bias.  Irrigation based farming may favor authoritarian political structures, while terrestrial hunter and gatherer societies may have a natural bias towards a more democratic political bent.

A religion's metaphysical structures and concepts don't matter much.  Mostly, in practice, religion serves as an embodiment and means of transmitting a set of values and collective organization techniques and structures associated with a particular method of food production.  Iron age Judaism and current era 7th century Islam both coded similar herder values and modes of collective organization, even though the former has only angels, while the later has both angels and jinn, as subordinate metaphysical actors.

Different forms of the same religion can occupy different places in this typology of religions.  Iron Age Judaism as it was practiced then may embody a set of values and collective organization associated with a different mode of food production than Rabbinic Judaism.  Southern Baptist Christianity as practiced may embody a different mode of food production than Episcopalianism.  In terms of their cultural message two religions with the same name, overlapping ceremonial components, and the same holy scriptures may be entirely different in practice.

The cultural message and collective organization approaches that a religion as practiced codes is much more important than the labels and window dressing of metaphysics that officially embody a religion's core metaphysical doctrines which can be deceiving and create a false sense of unity where none exists in the important essentials.  Interpretive doctrines have a great capacity to overcome otherwise obvious direct pronouncements of an ancient religious text.  Contrawise, it is possible to have a coherent culture associated with a particular mode of food production, in some modes of food production anyway, without some of the metaphysical elements we have come to think of as definitional components of a religion.  For example, concepts like karma and tao can be perfectly servicable alternatives to a metaphysical structure in which the way the metaphysical power acts with moral purpose in the world is through anthropomorphic beings conceptualized as "gods" rather than as pervasive cosmic forces or principles.  There may be some metaphysical structures, however, that are an easier fit to particular methods of food production and collective organization than others.  The natural tendency is to have a metaphysical world whose organization mirrors the way people understand their own world to really work.  Structures like the feudal language of the Christian New Testament, or the Olympian Council of Greek mythology mirror the political structures of their days.  Animist metaphysical structures may come naturally to people in hunter-gatherer societies who live at the whim of the countless plants and animals around them rather than the judgments of select groups of human leaders.

Connecting this economically determinist chain of reasoning together, the content of real world religions suddenly becomes far less random.  Rather than being arbitrary, a religion as practiced by a particular group of people at a particular time starts to look like something largely determined by the technologies and ecological circumstances that are formative for its adherents, which in turn drive their mode of food production in their formative period, which in turn drives the values and collective organizational forms that work best, which in turn drives much of the substantive content of the religion of those adherents as they practice it.  When a society has more than one mode of food production operating as parallel subcultures of the society at the same time, each subculture or caste of each society that practice a particular mode of food production may have its own way of practicing its religion, even if some or all of them on the surface claim to be practicing the same religion, or at least, the "true" version of the same religion.  Complex societies with multiple subcultures and centeralized government may need either a doctrine that calls for the toleration of multiple religious views as the First Amendment to the United States Constitution does, or a religion succeptible to have subcultures within it that publicly claim to be the same creed, in order to function.

When a society undergoes a transformation in its food production mode, sooner or later, its religion as practiced will catch up, although there may be some lag time from a most recent formative period to the present particular when a society or subculture is evolving to a new food production mode rapidly.  It may take a number of generations, for example, for a religion which was a herder religion in its most recent formative period to adapt to the economic realities of the present through intepretive, organizational and ritual adjustments.  For example, many religions practiced in the United States are in the process of adapting to new conceptions about gender and sexual orientation which are driven by a shift towards a postindustrial mode of economic organization which are driven by  new technological developments within the options made available by our evolving ecological constraints like those associated with the tail end of a century old petroleum based economy.

While not entirely inevitable, and while the specific formalisms and symbols that a religion expresses itself may be driven by historical baggage and may be path dependent, the substantive aspects of a religion that influence how people act in real life a strongly biased by economic realities that are in turn strongly biased by technological realities.  People who have values and inclinations about how to organize people in the society that work for its current stage of development and mode of food production will prospect and religions that reflect these views will prosper with them or be intepreted to become congruent with them, while people who have values and inclinations about how to organize people that are a poor fit for the current mode of food production will not prosper and religions that reflect their values will stagnate or die.

Denisovan Dilution Revisited: People Of The Dog?

In my post yesterday, I dismissed the possibility that the presence of Denisovan DNA in populations to the east of Wallace line and its absence to the west of the Wallace line was not easily explained by dilution of the Denisovan admixed population because East Indonesia has a substantial Paleolithic substrate and because the level of dilution required (on the order of a factor of sixty for South China relative to Papuans) would be so great. Have I dismissed this possibility too easily?

The evidence can be marshalled to give some support to a dilution narrative.

A Dilution By Paleolithic Y-DNA Haplogroup O Men Scenario

There is a stark difference in Y-DNA haplogroup frequencies on either side of the Wallace line. To the east are high frequencies of populations typical of Sahul populations (i.e. Australia and Papua New Guinea), with a modest amount of Austronesian (i.e. Neolithic seafarer) contribution that there is very strong evidence to suggest dates to the last five thousand years or so. On the other sided of the line, for example, on the island of Bali, the percentage of Y-DNA that is something other than Y-DNA haplogroup O is quite small, about 4%, with some of the Y-DNA haplogroup O attributable to Austronesian sources and some attributable to some other migration into Western Indonesia. While the ratio isn't quite sixty to one the cline is certainly steep and could explain much of the variance in Denisovan admixture.

One plausible time for the non-Austronesian lineages of Y-DNA haplogroup O to arrive in Western Indonesia would have been when Sundaland was attached to mainland Asia. The region where non-Austronesian lineages of Y-DNA haplogroup O are common correspond to the territory of Sundaland which was a continuous land mass attached by land to mainland Asia during the Last Glacial Maximum around 20,000 years ago. Even for people with some seafaring abilities more primative than that of the Austronesians, mass migration across land is easier than mass migration across water and the distribution of these lineages closely matches a terrestrial passage at that point in time.

This isn't the whole story, however. We know from a wealth of historical examples that when farmers and herders encroach onto the territory of a hunting and gathering population, that the former's advantages in terms of numbers and technology almost always overwhelms the hunters and gatherers resulting in major demographic shifts towards to food producing migrants. But, it is not at all obvious, in general, that one hunter-gatherer population ought to be able to overwhelm another hunter-gatherer population without a good reason. And the farming and herding were not developed until long after the last glacial maximum that lowered sea levels of join Sundaland to mainland Asia (nor, for that matter, was pottery).

One can easily imagine good reasons in a first contract between modern human hunter-gatherers and Denisovan hunter-gatherers. But, how can we explain how first wave migrants kindred to the Sahul population wave, could be totally dominated by the people who were bears of non-Austronesian lineages of Y-DNA haplogroup O?

After all, the kin of the Sahul population were notable for their superior maritime accomplishments relative to all hominins who came before them and to all who came afterwards until the Austronesians. The people of Sahul were able in a historical eye blink to bring about the extinction of megafauna every bit as frightening and huge as the monsters in fairy tales, without even having metal weapons or armor. Arguably the people of Sahul were exceptionally advanced and hence an unlikely candidate to fall en masse to the migration of another Paleolithic hunter-gatherer population into their territory. They managed to island hop across Western Indonesia when it was not connected by land into a single Sundaland penninsula, to cross the Wallace line, and to cross the sea from Wallacia to reach Sahul. In contrast, the non-Austronesian lineages of Y-DNA haplogroup O apparently needed a land bridge and never managed to cross the Wallace line in large numbers and didn't cause the extinction of ferocious giant predators.

I put aside, for the moment, the argument that these were non-Austronesian Neolithic migrants at the time that they came to Western Indonesia, because it stretched estimates of the age of these lineages more than one would like, is not associated with any known Neolithic population, and may not be necessary for the reasons set forth below.

The Dog Domestication Advantage.

So, what could the Paleolithic Y-DNA haplogroup O people have had twenty thousand years ago that gave them a decisive advantage over the awesome hunters of the first wave migrants who were kin to the Sahul people in Western Indonesia that left the first wavers totally marginalized even before the Austronesians arrived?

The most plausible explanation I can muster is a simple one. The Paleolithic Y-DNA haplogroup O people had domesticated dogs; the people who were vastly diluted by them did not.

The Sahul people did not have dogs until an archaeologically well documented moment when a handful of dingos migrated to Australia around 8,000 years ago from a stock found in Southeast Asian wild dogs. The arrival of the dingo in Australia caused a continent wide secondary mass extinction that eliminated many species that had survived the megafauna extinction that accompanied the appearance of modern humans in Australia. This mass extinction is a testiment to the impact that domesticated dogs could have on hunting and gathering economics.

Sahul populations certainly didn't have dogs twenty-thousand years ago, long before the dingo was introduced. So it stands to reason that their kin in Island Southeast Asia didn't either.

The domestication of dogs took place long before any of the other plant or animal domestications associated with the any of the several independent Neolithic revolutions. But, dog domestication had to have happened by the time that the founding population of the Americas arrived in Beringia right around the time of the Last Glacial Maximum and the existence of the Sundaland penninsula as a terrestrially connected land mass connected to the Southeast Asian mainland. In other words, dog domestication probably happened before peoples with men predominantly from Y-DNA haplogroup O swept across Western Indonesia.

While different studies reach different conclusions, some of the efforts to identify the principle ancestral source of the overwhelming majority of modern domestic dogs suggest a Southeast Asian progenitor, near the likely geographic point of origin of the non-Austronesian lineages of Y-DNA haplogroup O.

Dogs can explain how a Paleolithic hunter-gatherer population with dogs could totally marginalize a Paleolithic hunter-gatherer population without them. Since the advantage provided by dogs to hunter-gatherer populations are largely limited to terrestrial hunting and gatherering, the domestication of dogs could also shift the relative desirability of a terrestrial hunting and gathering strategy relative to a maritime fishing strategy, causing the maritime capabilities of populations that domesticated dogs to wither from disuse, particularly in areas where fishing had previously been only marginally superior to terrestrial hunting and gathering as a food collection method.

Y-DNA haplogroup O must have arisen sometime after first contact with the Denisovans. Its phylogeny makes clear that it isn't as old as the Sahul Y-DNA lineages. If Y-DNA haplogroup O arose in an area that was temporarily purged or nearly purged of Denisovan populations by the direct effects of the Toba eruption when humans first settled there (i.e. leaving Denisovans in numbers not significant enough to have a meaningful interaction or impact on the modern humans migrating into the area anywhere but Java island and points to it east in Island Southeast Asia and in East Asia), then the ancestors of the modern humans who settled in mainland Southeast Asia, Borneo and Sumatra without going further, would not have been Denisovan admixed except from slight percentages due to back migrations from the kin of Sahul-like populations. And, one of these mainland Southeast Asian populations probably gave rise ot the Y-DNA haplogroup O lineages.

The high level of homogeneity of the Y-DNA haplogroups of East Asia similarly argue the point that extreme levels of dilution of prior Sahul-like waves of migrants though multiple waves of Paleolithic and Neolithic migration of populations who can trace their origins to Denisovan-free Southeast Asia, making any Denisovan ancestry that remains almost imperceptable, isn't all that implausibe in East Asia.

Other Possible Demographic Impacts Of Y-DNA O Expansion

Of course, the dog domestication advantage I suggest as a possible source for the expansion of men with Y-DNA haplogroup O could also have directly devistated any relict Denisovan populations, in addition to diluting the contributions of first wave modern humans admixed with Denisovans in the modern human gene pool in Asia.

An expansion of a population predominantly made up of Y-DNA haplogroup O men that really did have such a great advantage over other Paleolithic peoples could also have dramatically marginalized populations where Y-DNA haplogroup D was predominant except in places like the Andaman Islands, Japan, and LGM refugia in Tibet, that this population, which had inferior martime capabilities, could not reach.

Limits On Y-DNA O Expansion

The same jungles and mountains that provided an effective barrier to modern human migration into Denisovan territory in Asia prior to the Toba eruption, however, may also once it had grown back tens of thousands of years later, have also mutated the capacity of Y-DNA haplogroup O men to back migrate en mass and dilute into irrelevance the populations of South Asia until they received the further boost of Asian Neolithic technologies like rice cultivation that brought Austroasiatic peoples into Northeast India.

The Limits Of Early Sahul Wave Maritime Capabilities

It is also worth keeping in mind that proto-Sahulean maritime capabilities should not be unduly exaggerated. Yet, they managed to island hop across the small straights of Western Indonesia, across the Wallace line, and then from Wallacia to Papua New Guinea and Australia, respectively. Yes, there is some evidence of very early deep sea fishing in Melanesia at around that point in time. But, the developments we don't see also speaks volumes.

The proto-Sahuleans did not settle the remainder of Oceania. They also did not settle Japan or the Andaman Islands. The Azores Islands in Europe were not settled by modern humans until the Bronze Age, long after the Upper Paleolithic revolution in which the proto-Sahuleans seems to have participated. There is considerable genetic evidence that Papuans and Aboriginal Australians did not experience much population exchange at all starting shortly after their founding populations were established. It took twelve thousand years or so from the domestication of the dog to the introduction of the dingo to Australia and the introduction of the dingo to Australia shows strong genetic traces of being a single event. There is also no sign of meaningful modern human population exchange between Sahul (or its successors) until sometime after the introduction of the dingo (and perhaps no more recently than the expansion of the Austronesians).

This evidence suggests that the possibility that apart from just a handful of isolated instances of one way voyages beyond the line of sight involving only a very small Sahul founding population, perhaps numbering something on the order of a hundred people (Australian aboriginal tradition speaks of seven canoes at a time when there were no domesticated animals, even dogs), that their navigational capacabilities may have been limited to navigation within a line of sight to the mainland. It appears from the evidence that there was virtually no intentional maritime trade between Sahul and the rest of Southeast Asia from this twelve thousand year time period, and probably from as far back as 40,000 years ago until sometime quite a bit later than 8,000 years ago, perhaps as late as the point at which contact with the Austronesians began. Even if the original founding populations of Sahul and Wallacia were competent deep sea mariners, the Sahuleans themselves appear to have promptly lost this technology. When the sea ultimately separated Tasmania and the rest of Australia there was no maritime travel between the two across the relatively shallow straight. The much later development of martime capabilities in the waters between the Island of Formosa and mainland China that ultimately culminated in the Austronesian's extraordinary maritime capabilities seems to have been an independent development not traceable to the Sahulean martime tradition.

High Resolution Denisovan Genetics

Several commentators have reviewed the last high resolution sequencing of the Denisovian genome, but John Hawks does has done a lot of research on the ancient Neanderthal genome has some of the most insightful comments.

There is Denisovan admixture in Sahul populations but not other Asians

First, he notes that the detailed findings confirm prior results on Densisovan admixture:

The mixture with a whole-genome sample from Papua New Guinea is estimated at 6% Denisovan ancestry. Confirming the later paper by Reich and colleagues, the new analysis finds no significant evidence of Denisovan ancestry in a mainland south Chinese (Han Dai) individual, and can exclude it down to a very small fraction:

However, in contrast to a recent study proposing more allele sharing between Denisova and populations from southern China, such as the Dai, than with populations from northern China, such as the Han, we find less Denisovan allele sharing with the Dai than with the Han (although non-significantly so, Z = –0.9). Further analysis shows that if Denisovans contributed any DNA to the Dai, it represents less than 0.1% of their genomes today.

That is a mystery to be explained. How did Asians end up lacking any evidence of Denisovan ancestry, when the peoples of Sahul (Australia and New Guinea) have six percent? . . . The early modern humans who were the ancestors of present Sahulian peoples surely came from Asia, and they surely mixed with Denisovans there somewhere, right? But today there's no sign that present Asian peoples descended from those early Asian peoples.

A Narrative The Could Explain The Geography Of Denisovan Admixture

My most recent analysis of this mystery was in a post from a week and a half ago. First, I argue that Denisovans are either Homo Erectus or an admixed derivative of them, and that Homo Flores, in turn, is a Homo Erectus subspecies that has experienced island dwarfism. I'll restate and expand upon one plausible narrative below.

Caveats

To be clear, I'm not claiming that the evidence proves that this narrative is true. Instead, I want to suggest that this is a narrative that would consistently explain everything we know so far without making any assumptions more outlandish than necessary to fit the facts. It don't claim that there aren't only plausible narratives that could also be true, only that I can't come up with any more plausible narratives and neither has anyone else. This is a hypothesis, not a proof. I have also taken the indulgence of relying on memory rather than looking up the published articles that back some of my assertions on Southeast Asian population genetics that I read a couple of years ago or so, and hence not linking to them, in order to save time in the process of drafting an already long post.

An Admixture In Flores Only Scenario

In my previous post, I concluded my analysis with the following summary:

[I]t isn't inconceivable to me that almost all "Denisovian" admixture in modern humans is actually traceable to a dozen or two instance of admixture with members of the species Homo Flores on the island of Flores, and that a strong flight instinct of Homo Erectus population members who did not experience dwarfism and had someplace to which they could flee, together with a modern human perception of those who did not experience dwarfism as more primate than fellow hominin, could have meant that there was no meaningful amount of archaic hominin admixture anywhere else in Southeast Asia or East Asia (with a possible exception probably involving even fewer instances of admixture relative to the founding population in the Philippines).

Why Not A Dilution Hypothesis?

One of the key reasons to favor a Flores admixture location over a mainland Asian one, in the 20/20 hindsight of the known facts that I didn't mention in my previous post is that too much of the population genetic makeup of island Southest Asia is too old to be explained by a land bridge crossing along the then geographically united Sunda penninsula during the Last Glacial Maximum. Likewise it is not a good fit to a predominant population source during the Austronesian expansion that is the source for the languages of the region just a few thousand years ago.

Genetically, some island Southeast Asia looks a bit like some of the populations of the far Northeastern corner of Europe. They show some of the highest levels of pre-Neolithic ancestry on their respective continents, only island Southeast Asia didn't have to be entirely repopulated after the Last Glacial Maximum from scratch, so its Paleolithic ancestry component is much older. (See also this paper on indigenous Malaysian genetics, this paper on Eastern Indonesian genetics, this paper, Island Southeast Asian genetics, here, this paper on Indonesian Y-DNA, Indonesian autosomal genetics, here, here, here, here, here, here, here, here, here, and here.)

This, together with the very low percentages of Denisovan admixture in island Southeast Asians relative to the Sahul populations, makes the most sensible scenario to explain the low levels of Neanderthal admixture seen in Europeans, i.e. archaic ancestry dilution by post-admixture waves of migrants look much less convicincing in Asia than it does in Europe.

The numbers for a dilution hypothesis work in Europe and are supported by the recent evidence of the Otzi genome. But, to explain the results via dilution, you need the Sunda and South Chinese populations to have experienced sixty times as much dilution as the Sahul populations, yet to retain in island Southeast Asia a very large percentage of early Paleolithic population genetics that is quite distinct from that of East Asia. After controlling for inferred levels of Austronesian gene flow, there is still a huge disparity in Denisovan admixture and even less of an explanation for how one Paleolithic modern human population could have so totally replaced a prior one. The genes of island Southeast Asian populations don't show that there was near total population replacement when these islands were joined to the mainland as part of the Sunda penninsula around 20,000 years ago. In short, the numbers just don't work to explain the geography of a Denisovan admixture with dilution from subsequent migration waves alone.

Suggestive Evidence To Favor Denisovans Flight And/Or Slaughter

The new high resolution study's conclusion that the Denisovans may have had a quite low effective population size is congruent, however, with a "flee don't f--k" scenario outside Flores, all of the way to Siberia. I've hypothesized for some time, based on the inferior tool kit found in Asia prior to the arrival of modern humans, that the population density of archaic Asians may have been quite a bit lower than the population density of Neanderthals or modern humans hunter-gatherers in comparably favorable environments. This inference is also suggested on the ground that Homo Erectus was also probably less intelligent than either Neanderthals or modern humans were given their brain case sizes relative to body size.

A greatly outnumbered, technologically inferior, less intelligent population of Asian Denisovans (i.e. late Asian Homo Erectus) would probably be more inclined to flee in the face of newcomers when they were so clearly outmatched, rather than trying to stand their ground and co-exist as the Neanderthals, who were probably a more equal match for modern human newcomers, apparently did. Since the Denisovan's had a smaller population, they might have a greater capacity to flee as well, at least on the mainland, where they weren't cornered.

Of course, seeing some of their peers who didn't flee get slaughtered by incoming modern human tribes could easily have helped motivate the Denisovan decision to flee rather than fight or co-exist with modern humans. We can probably never know if how violent the first contact events were for sure. Given the record of megafauna extinctions likely caused by modern humans, the income modern human tribes would probably have been capable of carrying out a Denisovan genocide leaving only a tiny diasporan population in places like Siberia and Flores, whether or not they actually did so.

How Did Denisovans Hold On So Long Before Collapsing?

My best guess is that the main reason that intellectually and technologically outmatched Denisovans were able to hold out for so long despite potential competition from rival archaic and modern hominin populations is that the jungles of Southeast Asia and the mountains of Zomia were an effective barrier to the migration of populations of archaic hominins large enough to be threatening to small tribes of Denisovan hunter-gatherers.

The Toba Eruption Opens The Gates To Southeast Asia

This may have changed when ash fall from the Toba explosion ca. 75,000 temporarily killed of the jungle. The eruption would also have reduced the population size of the Denisovans in the area between South Asia and Southeast Asia who used to live there. Even if the Toba explosion by itself wasn't sufficient to wipe out a Denisovan population, if it had had the luxury of recooperating without competition from other slightly more fit hominins, it may have so depleted Denisovan populations in this region that they promptly went extinct in this range under the additional indignity of an inmigrating population of modern humans who outnumbered them and were even slightly better hunters in the suddenly unfamiliar volcano ash ravaged landscape than they were, particularly in light of how static their lithic culture was, which suggests that they may have not been very innovative or adaptable.

The ash fall area from the Toba eruption is much more consistent with an event that opens the door for migration from South Asia to Southeast Asia than it is with an event that drives the large Out of Africa migration in a single wave all the way to Asia (see also here). This region would have been much harder hit by the Toba eruption than the more distant territory in South Asia where we know that modern humans encountered Toba ash fall. So any barrier effect that the presence of existing Denisovan tribes presence may have posed would have also been eliminated at least temporarily.

Toba ash would have fallen upon and reduced the habitability of all of what is now Burma, Thailand, Malaysia, Cambodia, Laos and Vietnam, the island of Hainan in South China, much of the island of Borneo, all of the island of Sumatra in Indonesia, the island of Palawan in the Phillipines, and just a little bit of western Java. But, most of the island of Java, the Philippines (except the island of Palawan), and everything east of the Wallace line, would have had no direct effects from the Toba eruption.

The parts of island Southeast Asia and the Phillipines other than the island of Java and a few islands in the Phillipines that weren't mostly within the ashfall area of the Toba eruption is a good match for the areas where there appear to be traces of Denisovan admixture, while none of the areas within the ash fall region of the Toba eruption show any trace of Denisovan admixture.

Denisovan Cave itself, in Siberia, would have been connected to the part of East Asia where Toba's ash did not reach, and would have been within the northern reach of the archaeologically estimated range of Homo Erectus. So, modern humans populating the vacuum left by the Toba eruption may have encounted very few Denisovan's relative to their own numbers if this is when they made their entry into the Asian continent (a date consistent with reasonably calculated mutation rate ages in Asia) until they had made their way all the way from India to South China.

Furthermore, it appears that the Northern part of the Denisovan range in Siberia and maybe even Northern China, may have been entirely depopulated during the last glacial maximum, and much of the intermediate territory consists of highlands in Zomia, Tibet, and Mongolia (see the paleoclimate map here) where I am not aware of any evidence of Homo erectus archaeology. If the Denisovans like the Neanderthals didn't have the ability to make weather proof shelters of their own and craft warm clothing, these places may have been inaccessible to them. The only lowlands between the Denisovan Cave (which can be reached via mountain valley passes for the most part that are warmer than the Central Siberian steppe to the north, or through the Central Siberian Plateau during the summer), and the eastern fringe of the Toba ash fall area in mainland Asia, are in Eastern China, Korea and Manchuria. The modern human edge over the Denisovans in these areas which were not as tropical, may have been greater than it was in Southeast Asia and South China.

The archaeological evidence shows that modern humans had already left Africa at least 25,000 to 30,000 years before this eruption. And, we know that there were modern humans in South Asia who survived the Toba eruption who could have taken advantage of the new migration options the temporary destruction of Southeast Asian jungles by ash fall could have opened up. We also know from African population genetics, that a large tropical jungle such as the Congo could be just as formidable a barrier to the migration of sustainable paleolithic hunter-gatherers as an ocean or a high mountain range.

When the Toba eruption opened, it the gates of the region to modern human populations already resident in South Asia, and they surged into Southeast Asia. The Denisovans retreated before there was any meaningful opportunity for admixture all the way to Siberia. Island Southeast Asians had less of an opportunity to flee, but these quite small populations of non-dwarf late Homo Erectus may have seemed too threatening to the early modern human populations to be tolerated and may have instead have been simply wiped out (or at least were not integrated socially enough to give rise to admixture).

Denisovan Matings May Have Been Less Fruitful Than Neanderthal Matings Due To Greater Genetic Distance

Given that Denisovans were more genetically distant from modern humans than Neanderthals (probably more like 1,800,000 years of separation instead of 500,000 years of separation), it may also have been the case that the yield of fertile offspring from mating between Denisovans and modern humans may have been lower, and hence a longer period of co-existence may have been necessary for a comparable level of introgression into the modern human population to accumulate.

Prolonged Co-Existence On Flores Would Have Allowed Plenty Of Time For Introgression Even With Very Few Fertile Hybrids

But, this could have happened during the archaeologically long period of co-existence (tens of thousands of years) between modern humans and Homo Flores on the island of Flores which is geographically cheek by jowl. In this context, introgression could accumulate over a considerable amount of time (perhaps 25,000-30,000 years) even if the interspecies couplings weren't very fertile on average. If the modern human effective population size was small, it wouldn't take many successful interspecies hybrid children per generation on average in the 1,000 generations of co-existence between a hypothesized Toba explosion driven entry of modern humans in the region and the colonization of Sahul by modern humans.

Alternatively, perhaps an initial modern human population in Flores had an effective population size of only a dozen or two individuals (or less), which is quite possible if the gene pool of the Sahul migrants was subsequently expanded by a small number of Upper Paleolithic people as I suggest below, given current levels of genetic diversity of these populations. This would make sense in a scenario in which the original modern humans in Sahul were shipwrecked there and didn't have the maritime skills to intentionally navigate across the Wallace line or to Sahul until Upper Paleolithic people arrived. If this was true, and admixture took place only in the initial moment of the most dire population bottle neck, one could obtain all of the observed level of Denisovan admixture in the Sahul populations from just one or two pregnancies in the first generation. It should probably be possible to estimate the effective population size of the Denisovan population that contributed to the Sahul gene pool with enough high resolution genomes from that population to describe the diversity in the parts of their genome not found in other modern humans, and an analysis that showed that this effective population was just one or two individuals wouldn't surprise me, although it certainly isn't compelled by what we know so far.

In a slight variation of the shipwreck scenario that has the virtue of relying less on random chance, perhaps there was just one instance of Denisovan admixture (either just one fertile hybrid child, or one Denisovan-modern human mated couple with multiple children) on the island of Java. Perhaps due to hunting and gathering competition from modern humans, and perhaps due to warfare with modern humans as well in which the Denisovan's were outnumbered and outfought (and at hunter-gatherer population densities, the populations of both groups on the island of Javan would have been quite small - there were perhaps 45,000 Neanderthals by a census measure in all of Europe and Java was much smaller than Europe), the Densivoan of Java were pushed over into extinction soon thereafter. Perhaps the family of the hybrid child was persecuted by the other modern humans on the island. Perhaps the hybrid child and a small group of supporters made up of extended family and close friends were willing, in order to flee this persecution in a way that would leave it forever behind them attempt a risky one way trip across the straight and hence across Wallace line with inferior early Paleolithic rafts. In this scenario, the migrants would have had no interest in even trying to return to Java and hence no incentive to refine their successful boat design. This scenario would also produce the admixture ratios we see today in the Sahul population.

Expansion Into Sahul May Have Required An Upper Paleolithic Boost

The expansion from Flores or some other island on the east side of the Wallace line to the Sahul may have been faciliated by advantages associated with the arrival of a second wave of modern humans, who were integrated with first wave modern humans before expanding further to the Sahul. This second wave may have been expanding themselves due to the advantages, whatever they were, that drove the larger Upper Paloelithic revolution.

For example, in a scenario that also keeps the initial population size of modern humans in Flores low enough to make it sensible for them to treat Homo Flores on a more equal footing that their kin in Southeast Asia had previously, perhaps the first wave modern human residents of Flores arrived only by maritime misadventure and didn't have the boating technology to return back across the Wallace line to their fellow modern humans. This group of shipwrecked men and women wouldn't have been nearly as impressive and intimidating to the indigeneous archaic hominins as the intentionally migrating populations who crossed the less daunting waters on the other side of the Wallace line, and as dwarves, wouldn't have been seemed like as much of a threat to the shipwrecked men and women.

These first wave modern humans may not have had the capacity to intentionally navigate across the Wallace line or beyond to Sahul in large enough numbers to establish a sustainable population. This capacity may have arrived only much later when a small population of much more competent mariners at the most distant fringe of Upper Paleolithic revolution population expansion, informed by the technological advances of the Upper Paleolithic revolution, arrived and were integrated into the existing population in Flores. By the time the wave of newcomers appeared on the scene, the first wave modern human population may have already received considerable Homo Flores introgression into the small modern human population of Flores over a thousand generations of co-existence on that island that was carried on by the migrants to the Sahul.

This two wave migration theory would explain another of the long standing mysteries of Paleolithic migration in Asia. There is pretty good archaeological evidence pointing to the time that Sahul was first colonized by modern humans about 45,000 years ago. The genetic evidence indicates that the founding population of Sahul was quite small but was phylogenetically quite diverse and also that the Papuan and Australian proto-populations underwent a schism almost immediately upon arrival, with both branches having almost all parts of this phylogenetic diversity. Yet, there were modern humans in South Asia at the time of the Toba eruption and there were modern humans in mainland Southeast Asia at least 63,000 years ago.

Why did it take so much longer for them to reach the Sahul than the rest of Asia?

Modern humans made it from Beringia to the far reaches of South America in just a few thousand years and the distance from mainland Southeast Asia to Papua New Guinea and Australia is much shorter. A scenario with a first wave of modern humans who managed to cross the Wallace line only by accident and a second wave of Upper Paleolithic modern humans who could do it on purpose a thousand generations later, would explain this gap. One of the things that may have made the Upper Paleolithic era revolutionary may have been a revolution in boating technology.

The measured levels Neanderthal admixture in Asians relative to Europeans contradicts prior research.

Second, Hawks notes that their finding on the relative levels of Neanderthal admixture differ from prior research:

To me at the moment, this is the most interesting paragraph of the new paper:

Interestingly, we find that Denisovans share more alleles with the three populations from eastern Asia and South America (Dai, Han, and Karitiana) than with the two European populations (French and Sardinian) (Z = 5.3). However, this does not appear to be due to Denisovan gene flow into the ancestors of present-day Asians, since the excess archaic material is more closely related to Neandertals than to Denisovans. We estimate that the proportion of Neandertal ancestry in Europe is 24% lower than in eastern Asia and South America (95% C.I. 12–36%). One possible explanation is that there were at least two independent Neandertal gene flow events into modern humans. An alternative explanation is a single Neandertal gene flow event followed by dilution of the Neandertal proportion in the ancestors of Europeans due to later migration out of Africa. However, this would require about 24% of the present-day European gene pool to be derived from African migrations subsequent to the Neandertal admixture.

This is a very interesting result, partially because it is the opposite of what we are finding. As I explained earlier this year, we are finding Europeans to share more Neandertal alleles than Asians do. The difference in our results has been much smaller than 24%; really only an increase of less than 0.5% on the whole genome, or maybe 10% relative to the overall amount in Europe (which is on the order of 3%).

Hawks considers some possible sources of the discrepency. Given the flat contradiction between the studies using methods whose differences are subtle, it is hard to know the cause of the discrepency. On balance, my intuition is to give greater credit to the findings of Hawks group, because his group studied much larger sample sizes and their is some meaningful variation in Neanderthal admixture levels in Eurasians in the 1000 Genomes sample. The large discrepency may simply be a matter of random chance whose statistical significance (Z=5.3) is overestimated because the data are more structured than the statistical assumptions from the new study, using samples from just three European and two Asian populations assumes.

The question of whether there was one round of Neanderthal admixture, or two or more with some regional differentiation that just happened to produce roughly similar levels of Neanderthal admixture since the processes were similar and played out in similar ways, is beyond the scope of this post and complicated by the discrepencies in the reported empirical results.

Denisovan Effective Population Size Was Small And Fell When Modern Humans Appeared

Third, he notes that there are indications in the genomic evidence of population decline in Denisovans and Neanderthals to a low effective population size coinciding temporally more or less with the arrival of modern humans:

It has become possible to make some good estimates of demographic history using only a single diploid genome, using a technique developed by Li and Durbin. Meyer and colleagues applied this technique to the Denisova genome, finding that its genetic history contrasts with that of living human populations:

To estimate how Denisovan and modern human population sizes have changed over time we applied a Markovian coalescent model to all genomes analyzed. This shows that present-day human genomes share similar population size changes, in particular a more than two-fold increase in size before 125,000–250,000 years ago (depending on the mutation rates assumed). Denisovans, in contrast, show a drastic decline in size at the time when the modern human population began to expand.

There is not yet enough data from Neandertal genomes to apply the same method, but to the extent that we understand their diversity, they show a similar picture. These archaic humans in Eurasia had much, much smaller effective population sizes than the ancient population of Africa.

Of course, we know for a fact that the Denisovan are no more, that they co-existed at least briefly with modern humans, and that modern human population size has grown over time. Any model that indicated something different when applied to the data would have to have been wrong, and the confidence intervals for the dates provided by the model are wide enough to fit all of the plausible scenarios. There is also considerable mischief that goes into interpreting what effective population size means in the context of a very late relict population of a species on the verge of extinction that Hawks explores a little.

But, as I've noted above, there are plausible reasons to think that Asian Homo Erectus might have had a fairly small effective population size that fell when modern humans arrived and that the Denisovan reflects Asian Homo Erectus ancestry.

Could Higgs Boson Bump Be A Mix Of Mesons?

John Moffat, a physicist at the Perimeter Institute also known for one of the lesser known relativistic modified gravity proposals, explores the possibility that the Higgs boson resonance could be a linear combination of two heavy quark mesons aka quarkonium (top-antitop and bottom-antibotton) using a mixing angle from existing physics, which would be pseudoscalar (i.e. a composite particle with an overall spin of zero, rather than a fundamental particle with spin zero).

He also describes the experimental tests necessary to distinguish the two possibilities which would in may respect have very similar properties. The easiest way to distinguish the two is via the spin-parity of the particle which could be determined through analysis of the angular distribution of the particle's decay products.

His proposal culminates about five years of papers he has written on Higgsless versions of the Standard Model.  While he is a frequent advocate for unconventional theoretical explanations of the evidence in fundamental physics, he is no crackpot, he is asking the right kinds of questions, and his proposals of experimentally testable alternatives to the Standard Model that don't involve SUSY is a valuable one that deserves more attention in contexts like analysis of LHC results.

Stray Thoughts

* Razib's pinboard at Gene Expression notes the Wikipedia article on the Vedda language. Until it became extinct or moribund in the 1990s it was the language of a hunter-gatherer group of Sri Lanka. It was one of the last South Asian languages that was originally neither part of the Dravidian nor the Indo-Aryan nor the Austro-Asiatic nor the Tibeto-Burman language families of South Asia, although continued exposure to the local Dravidian language over 2,500 to 3,000 years resulted in substantial borrowing of words between the two, with some Vedda words borrowed from early Dravidian dialects that are no longer used in modern Dravidian languages.

The Vedda language is a vivid reminder of that fact that 6,000 years ago, almost nobody in India spoke either the Dravidian languages, which started to rapidly expand with the South Indian Neolithic around then, or the Indo-Aryan languages, which probably appeared in South Asia around 4,000 years ago. Austro-Asiatic languages (i.e. the Munda languages of South Asia) are probably roughly contemporaneous in their arrival from Southeast Asia with these two language families and probably arrived around the same time as rice cultivation began in India. The Tibeto-Burman languages are the most recent arrivals in South Asia and form the most genetically distinct populations of India. Most of the preceding South Asian languages went extinct in prehistory before they were attested. But, it is a mistake to think of the Dravidian languages as the language family of the indigeneous hunter-gatherers of India since times immemorial. If Proto-Dravidian was indigeneous to India at all, it was probably spoken only by one small tribe that happened to be the first to master farming in the region.

* Similar points about the pre-Indo-European linguistic landscape can be made about Europe at a fairly similar time depth (at least relative to the appearance of the Neolithic revolution there).

* I have never really taken seriously the possibility that there could have been Bronze Age maritime trade with West Africa, even though there was martime trade with East Africa at least as far back as the early Iron Age and quite possibly much earlier. But, a new post at Maju's blog notes increasing evidence of Bronze Age maritime colonization of the Azore Islands in the Atlantic Ocean. West Africa would have been no harder to reach. So, the possibility of Bronze Age maritime trade with West Africa while still somewhat doubtful, is no longer something that seems highly unlikely.

* The use of the wheel for practical transportation purposes is about 5,500 years old and probably originated in the Pontic-Caspian Steppe. The existence of a common source word for this in Proto-Indo-European lingustic reconstructions argues for the youth of this language family and its origins on the Steppe, as do borrowings of even very archaic forms of Indo-European words into Uralic languages.

* It is not at all obvious that the root of the Anatolian Indo-European languages (most famously Hittite), is in fact in Anatolia. The earliest attestations and archaeological indications of the earliest cores of the Hittite people and the Indo-Aryans is about 4,000 years ago and both populations introduce metal working techniques that were invented only a little earlier in the Caucasus mountains. Other kinds of historical and archaeological evidence point to both as being intrusive, and the arrival of Indo-European Greek speakers in the Aegean region is a historically attested event and happened within the last 4,500 years.

* Early Iron Age Judaism, as described in the Torah, looked a lot more like modern fundamentalist Islam in practice than it does like the Rabbinic Judaism of the last two thousand years. The last two thousand years also marks a time, when, despite significant modern endogamy preferences among Jews, the genetic evidence indicates that the people of the Jewish diaspora admixed heavily with non-Jewish peoples. By ancestry, Ashkenazi and Sephardi Jews are much less Semitic than, for example, modern Saudi Arabians.

Irrigation Incompatible With Democracy

An in depth analysis shows that irrigated farming, measured not by actual irrigation, but by potential crop yields from irrigation, is a causal factor in authoritarian government structures.

Presumably, the theory is that the coordination of effort required to establish and manage irrigated agriculture requires centralized authority and that the easiest way to achieve such centralization is with an authoritarian government whose legitimacy flows from the value added by the irrigated farming system relative to the status quo. Rainfall based agriculture apparently does not empirically show such strong tendencies towards authoritarian government.