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Monday, October 17, 2022

Paleo-Formosans

A new study has found human remains in Taiwan from 6,000 years ago the support the existence of Paleo-Formosan Negrito people on the island who were very similar to Northern Philippine Negrito people, who may have persisted in relict populations in remote mountains on the island until the late 1800s. 

This doesn't precisely contradict the existing paradigm for the narrative of Formosan pre-history, although it does expand it and solidify it.

The study did not recover ancient DNA. This post provides some context to the find and then provides the abstract to the article and a citation to it.

Modern Taiwanese People

Most people in Taiwan (on the island of Formosa) are ethnically Chinese. Many of the Chinese people who live there are Nationalists who were politically to the right of communists and migrated there when the Chinese Community Party won the civil war between the Nationalists and the Communists of the years 1946-1949 in 1949, somewhat like the old regime Cubans who migrated to Florida when Castro turned Cuban in a communist regime.

The ethnically Chinese people of Formosa marginalized and demographically overwhelmed the indigenous farmers and fishers of Formosa which include an ethnic grouping ancestral to the Austronesian people.

The Austronesian People

In historical linguistics and anthropology the focus is on the "indigenous" people of Taiwan from several different linguistic groups, one of which is the parent language of the Austronesian languages spoken in Oceania, much of Southeast Asia, and Madagascar in an expansion that began around 2000 BCE. (The expansion had run its course by about 1000 CE with many intermediate steps, with the linguistically Austronesian people of Madagascar, for example, deriving from a specific narrow geographic area of the island of Borneo in which is now Indonesia.) 

In island Southeast Asia and Oceania, as well as in Madagascar, the first wave of farmers were linguistically Austronesian, a language family that has been traced to a particular tribe of indigenous post-Negrito Formosans, although Austronesian languages are also spoken in some coastal areas. Austronesians encountered, sometimes replaced and sometimes admixed with, previous Papuan and Negrito Southeast Asians.

These indigenous people of Taiwan were farming and fishing people who migrated there from what is now Southern China in the late Neolithic era or the Bronze Age. Thus, the proto-Austronesians in turn originate in the South Chinese Neolithic rice farming revolution, as do essentially all other pre-European colonial era waves of migration to Southeast Asia.

The Austroasiatic People And Subsequent Waves Of Migration To Southeast Asia

In Southern mainland China, mainland Southeast Asia, and northern India (the Munda people), the first wave of farmers were linguistically Austroasiatic, a language family that originates in the South Chinese rice farming Neolithic revolution. There were also later waves of migration of farmers from South China, most recently the Thai people.

The Austroasiatic people (and possibly the Austronesian people as well) expanded away from South China, in part, due to southward migration from the original North Chinese millet farming Neolithic revolution which is the source for the Han Chinese ethnicity that has since become predominant in most of mainland China with substrate influences from Southern Chinese people who were mostly peacefully integrated into the Han Chinese political and linguistic sphere.

The Negrito People Of Asia

But before this indigenous people arrived, there was a Negrito population in Taiwan closely related to the Negrito hunter-gatherer populations of Southeast Asia. Taiwanese Negrito people were particularly similar to the Negrito people who still exist in relict population of the Northern Philippines. 

Negritos are dark skinned (hence the name), and short in stature, with at least ancestral roots in terrestrial hunter-gatherer populations, but are fully modern human and are no more closely related to dark skinned Africans than any other Eurasian or New World population. Their dark skin and small size are examples of convergent evolution since those traits were selective fitness enhancing in the tropical Southeast Asian places that they lived. In mainland Southeast Asia, the prehistoric peoples who gave rise to modern Negritos are called "Hoabinhian hunter-gatherers". 

Negritos have genetic affinities with the Onge hunter-gatherers of the Andaman Islands and with the pre-Neolithic people of Southern India who ancestry is an important component of the genetic makeup of the modern people of Southern India (with the proportion being largest those of lower caste or "untouchables" or "tribal" ancestry who are socio-economically below lower caste Indians) although almost no one in Southern India today has this ancestry exclusively due to Bronze Age admixture with "Ancestral North Indians".

In the Neolithic era and metal ages, most Negritos were replaced in Formosa, mainland China, Southeast Asia and India's prime territory for human habitation by food producing farmers (a fate shared by hunter-gatherer populations almost everywhere), with relict populations persisting in marginal deep jungles and in mountains that weren't as suitable for herding and farming, and many transitioned from pure terrestrial hunting and gathering to herding.

The Negrito people are very distinct physically from the indigenous Jomon people of Japan who were present there before mainland farmers and herders arrived from Korea (although people similar to the Jomon people may have been present in Korea as well around that time ca. 1000 BCE). But there is some reason to think that they may have common genetic origins.

A TreeMix analysis places the Jomon as an offshoot of the Hoabinhian people (a Mesolithic wave of people in Southeast Asia and Southern China ca. 12,000 to 10,000 BCE), with the Kusunda people (who are hunter-gathers in Western Nepal who historically spoke a language that is an isolate and were animistic religiously) as an intermediate population.

Y-DNA haplogroup D has a cryptic distribution found in isolated pockets across Asia including Siberia and Tibet that tends to favor a Northern route origin.

The mtDNA haplogroups N9b and M7a also tell story so deep in history (both are very basal in the Eurasian mtDNA tree and derived from African mtDNA haplogroup L3) that it is hard to reconstruct. Both mtDNA M and mtDNA N show distributions that tend to favor a Southeast Asian route to Japan, but perhaps this is because the northern bearers of this haplogroup went extinct, and were then almost fully replaced in the Last Glacial Maximum.

On the other hand, there have continuously been modern humans in Japan since before the 12,000 BCE migration associated with the Hoabinhian people, so at least some Jomon ancestry probably precedes that wave of migration. But different selective pressures in Japan and Southeast Asia could also lead to selection for a different physical appearance.

But, at least one linguist has proposed that the language of the Jomon people (the only extant survivor of this language family is the language of the Ainu people who are now found only in Hokkaido, and Ainu's membership in this language family or families is mildly disputed), is part of an "Austric" megafamily root in South China, rather than being a language isolate.

Negritos Are Modern Humans Not Archaic Hominins

Negritos are completely distinct from archaic hominins who preceded modern humans in the region such as Denisovans (a sister clade of archaic hominins to Neanderthals in eastern Eurasia less basal than Homo erectus), to Homo erectus (who arrived in what is now Java, Indonesia from Africa around 2 million years ago and were found throughout Southeast Asia and East Asia), to Homo floresiensis (a.k.a. hobbits due to their physical size and build, remains of whom are found on the island of Flores, Indonesia; 2017 study concludes by phylogenetic analysis that H. floresiensis is an early species of Homo, a sister species of Homo habilis, which is more basal than Homo Erectus, although the time of their migration out of Africa is unclear) to diminutive archaic hominins of the Philippines somewhat similar to H. floresiensis

While all non-Africans have a small percentage of archaic Neanderthal admixture, modern humans only have archaic Denisovan admixture to the extent that they have Papuan and Australian Aboriginal ancestry. Among mainland Southeast Asians, East Asians, and island Southeast Asians who are from the west side of the Wallace Line, Denisovan ancestry is barely detectible relative to that proportion of Denisovan ancestry in Papuans and Australian Aborigines. 

This suggests that Negritos are either a second wave of modern human migrants to Southeast Asia and beyond with a small percentage of ancestry from a first wave of modern humans in these areas that admixed with Denisovans, or that the Negrito wave of migration in Southeast Asia and beyond was so much more numerous than in island Southeast Asia, that the few instances of Denisovan admixture were heavily diluted.

The overall percentage of Denisovan ancestry in modern Tibetan people is negligible and essentially impossible to detect, but fitness enhancing genes in Tibetans associated with tolerance for very high altitude environments are Denisovan in origin, indicating that some of their remote ancestors in the region must have had local Denisovan admixture.

No Y-DNA or mtDNA in any modern human is believed to be Denisovan or Neanderthal in origin.

Negritos Were Not The First Wave Of Modern Humans

Negritos were an  early wave of modern humans in a region that spanned from India to Taiwan including much of Southeast Asia, but probably not the first wave. 

The first wave of modern humans in Asia were the ancestors of modern Australian Aborigines and indigenous Papuans, and admixed with Denisovan archaic hominins. Archaeological evidence suggests that they first arrived around the time of the Toba volcanic mega-eruption around 70,000 years ago.

The Paper and Its Abstract
Taiwan is known as the homeland of the Austronesian-speaking groups, yet other populations already had lived here since the Pleistocene. Conventional notions have postulated that the Palaeolithic hunter-gatherers were replaced or absorbed into the Neolithic Austronesian farming communities. Yet, some evidence has indicated that sparse numbers of non-Austronesian individuals continued to live in the remote mountains as late as the 1800s. 
The cranial morphometric study of human skeletal remains unearthed from the Xiaoma Caves in eastern Taiwan, for the first time, validates the prior existence of small stature hunter-gatherers 6000 years ago in the preceramic phase. This female individual shared remarkable cranial affinities and small stature characteristics with the Indigenous Southeast Asians, particularly the Negritos in northern Luzon
This study solves the several-hundred-years-old mysteries of ‘little black people’ legends in Formosan Austronesian tribes and brings insights into the broader prehistory of Southeast Asia.
Hsiao-chun Hung, et al., "Negritos in Taiwan and the wider prehistory of Southeast Asia: new discovery from the Xiaoma Caves" World Archaeology (October 4, 2022) https://doi.org/10.1080/00438243.2022.2121315. Hat tip to DDeden in the comments.

5 comments:

  1. I have to be the "reply guy" here: Ayta Magbukon have the most Denisovan DNA at 5%. They are a Philippine indigenous community and Negrito.

    ReplyDelete
  2. They are generally believed to have significant Papuan ancestry (as do several ethnicities of indigenous people of the Philippines).

    ReplyDelete
  3. Source on the Papuan claim? I don't think the Ayta have anymore than a distant affinity there.

    ReplyDelete
  4. Speaking of archaic hominins: .9ma HSA2 fusion 23 paired chrom. Human, 24 in great apes
    BMC Genomics volume 23, Article number: 616 (2022)

    Abstract
    Background
    The reduction of the chromosome number from 48 in the Great Apes to 46 in modern humans is thought to result from the end-to-end fusion of two ancestral non-human primate chromosomes forming the human chromosome 2 (HSA2). Genomic signatures of this event are the presence of inverted telomeric repeats at the HSA2 fusion site and a block of degenerate satellite sequences that mark the remnants of the ancestral centromere. It has been estimated that this fusion arose up to 4.5 million years ago (Mya).

    Results
    We have developed an enhanced algorithm for the detection and efficient counting of the locally over-represented weak-to-strong (AT to GC) substitutions. By analyzing the enrichment of these substitutions around the fusion site of HSA2 we estimated its formation time at 0.9 Mya with a 95% confidence interval of 0.4-1.5 Mya. Additionally, based on the statistics derived from our algorithm, we have reconstructed the evolutionary distances among the Great Apes (Hominoidea).

    Conclusions
    Our results shed light on the HSA2 fusion formation and provide a novel computational alternative for the estimation of the speciation chronology

    https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-022-08828-7

    ReplyDelete