A new paper (open access) continues the ongoing effort to ferret out the nature of the archaic "ghost populations" that admixed with modern humans in Africa, sometimes relatively recently as evolutionary history goes. The archaic introgression percentages inferred statistically are on the same order of magnitude as Neanderthal and Denisovan introgression into the Eurasian populations where this introgression is found.
Razib discusses this paper and another one that I blogged a few days ago at Gene Expression. He notes that the genetic case for archaic admixture in Africa is solid but that the details should be viewed with some skepticism in light of the methods used to discern it. It would be interesting to see if the details of the new paper's model could be replicated from another different set of 21 individuals from the same 15 reference populations using the same methods.
Razib discusses this paper and another one that I blogged a few days ago at Gene Expression. He notes that the genetic case for archaic admixture in Africa is solid but that the details should be viewed with some skepticism in light of the methods used to discern it. It would be interesting to see if the details of the new paper's model could be replicated from another different set of 21 individuals from the same 15 reference populations using the same methods.
The paper is as follows (with a quick and dirty cut and paste with emphasis added in the abstract):
Whole-genome sequence analysis of a Pan African set of samples reveals archaic gene flow from an extinct basal population of modern humans into sub-Saharan populations
- Belen Lorente-Galdos†,
- Oscar Lao†,
- Gerard Serra-Vidal†,
- Gabriel Santpere,
- Lukas F. K. Kuderna,
- Lara R. Arauna,
- Karima Fadhlaoui-Zid,
- Ville N. Pimenoff,
- Himla Soodyall,
- Pierre Zalloua,
- Tomas Marques-Bonet and
- David Comas
†Contributed equally
- Received: 17 August 2018
- Accepted: 28 March 2019
- Published: 26 April 2019
Abstract
Background
Population demography and gene flow among African groups, as well as the putative archaic introgression of ancient hominins, have been poorly explored at the genome level.
Results
Here, we examine 15 African populations covering all major continental linguistic groups, ecosystems, and lifestyles within Africa through analysis of whole-genome sequence data of 21 individuals sequenced at deep coverage. We observe a remarkable correlation among genetic diversity and geographic distance, with the hunter-gatherer groups being more genetically differentiated and having larger effective population sizes throughout most modern-human history. Admixture signals are found between neighbor populations from both hunter-gatherer and agriculturalists groups, whereas North African individuals are closely related to Eurasian populations. Regarding archaic gene flow, we test six complex demographic models that consider recent admixture as well as archaic introgression. We identify the fingerprint of an archaic introgression event in the sub-Saharan populations included in the models (~ 4.0% in Khoisan, ~ 4.3% in Mbuti Pygmies, and ~ 5.8% in Mandenka) from an early divergent and currently extinct ghost modern human lineage.
Conclusion
The present study represents an in-depth genomic analysis of a Pan African set of individuals, which emphasizes their complex relationships and demographic history at population level.
Almost surely not. The divergence data inferred from the genetic data ca. ca. 600K-700K years ago. H. Erectus diverged ca. 1900K to 2100K years ago.
ReplyDeletewhen did h erectus become extinct?
ReplyDeletei thought humans diverged from h erectus earlier than this, and possibly is a hybrid
"when did h erectus become extinct?"
ReplyDeleteAt the latest, around 100kya. Possibly as early at 200kya. The archaeological record is pretty thin in that time frame. Of course, it would be easy to miss a small relict population that lasted longer in some niche environment isolated from whatever killed off everyone else.