Ambroise Wonkam & Adebowale Adeyemo, publish study suggesting primitive admixture in modern Africans. Dates align with Australopithecines
Ambroise Wonkam and Adebowale Adeyemo are medical doctors, immigrants from Africa. Both have had distinguished careers at East Coast medical facilities, and have received acclaim and awards for their work.
Ambroise Wonkam from his bio:
Prof Ambroise Wonkam is a professor of Genetic Medicine, and Director of the McKusick-Nathans Institute, and Department of Genetic Medicine.
After an MD training from the Faculty of Medicine and Biomedical Sciences, University of Yaoundé I (Cameroon), he completed a thesis in Medical Sciences, University of Geneva (Switzerland) and a Ph.D. in Human Genetics (University of Cape Town, South Africa).
Adebowale Adeyemo from his bio:
Dr. Adeyemo qualified in medicine at the University of Ibadan in Nigeria. After a residency in pediatrics and genetics, he became a faculty member of the College of Medicine, University of Ibadan, Nigeria and a consultant pediatrician/geneticist at the University College Hospital, Ibadan, Nigeria. He subsequently held fellowships in genetic epidemiology and in medical education. He moved to Howard University, Washington, D.C. in 2003 to work in genetic epidemiology at the National Human Genome Center at Howard University. He came to the NIH in 2008 as a Staff Scientist. He became an associate investigator at NHGRI in 2016.
The authors studied 12 different indigenous African populations from varying regions of the continent. The study was aimed at better understanding diseases and causes of various illnesses that affect specifically Africans and ethnic Africans living in the United States and other Western countries. The paper highlights sickle-cell anemia, and Covid 19 specifically.
However, of particular interest to the paleo-anthropology community, Wonkam and Adeyemo released data from their findings that points to deeply archaic hominin DNA admixture in modern Africans and Afro-ethnics. The data echoes similar findings from past studies, most especially geneticists Durvasula and Sakaraman, UCLA genetics, 2020.
See our article here at Subspeciest, March 2020, “West Africans have 19% archaic ghost species DNA according to New UCLA genetics paper.”
Background from the BBC, Feb. 14 2020,
‘Ghost’ human ancestor discovered in West Africa
Researchers suggest DNA from this group makes up between 2% and 19% of modern West Africans’ genetic ancestry.
They believe the interbreeding occurred about 43,000 years ago.
Scientists found links to the Mende people of Sierra Leone, Yoruba as well as Esan people in Nigeria, plus other groups in western areas of The Gambia.
Like Durvasula and Sakararaman before them, Wonkam and Adeyedo offer hints as to the identity of the hominin species responsible for the African archaic admixture. But they take it a step further giving specific dates of the three introgression events.
From Cell.com, March 8,
Leveraging our common African origins to understand human evolution and health
The authors data suggest that all modern humans derive approximately 5%–15% of their ancestry from a lineage that may have diverged as long as 1–3 mya, with multiple introgression events (Figure 1A ), which is in line with previous reports.
Generation of high-coverage reference genomes for archaic hominid species such as Neanderthals has allowed the identification of approximately 2% introgression portion of that genome in present-day Europeans, ostensibly enriched for variation in genes involved in dermatological phenotypes, neuropsychiatric disorders, and immunological functions, including host susceptibility to coronavirus disease 2019 (COVID-19).
In a similar vein, Fan et al. showed evidence of 2% content from Neanderthal genomes in African populations from Ethiopia, most likely as a result of admixture with non-Africans. However, these findings should be further interrogated directly with comparative analysis of more genomes from Ethiopians and available Neanderthal genomes. The largest challenge in expanding this area of research in Africa has been the inability to obtain high-quality ancient DNA from regions with a tropical climate where the heat and humidity rapidly degrade DNA. The recent report of the successful isolation and sequencing of DNA from four children buried at Shum Laka (Cameroon) 3,000–8,000 years ago indicates that studies of ancient DNA are now possible in western Central Africa.
The citation of Shum Laka refers to well-preserved skeletons of 4 children in southeastern Cameroon. They were identified as Pygmies, Baka and Aka tribes, who later moved into central Africa in the Congo.
From ZmaScience.org, 2020,
[They] had some DNA coming from an ancient source in West Africa — including a “long lost ghost population of modern humans that we didn’t know about before,” says population geneticist David Reich of Harvard University, leader of the study…
Wonkam and Adeyemo include a chart. From their description:
Complex demographic history of African populations consists of ancient population evolutionary divergence, including multiple introgressions of archaeid DNA within African genomes, as illustrated by a simplified demographic model indicating at least two introgression events from archaic human that never move out of Africa (blue lines).
Note – introgression is simply an academic, anthropological term meaning sexual encounters, mixing of genes.
Of particular interest to readers of this site, and to the overall right paleo-anthropology community, is the blue line. Three introgression events are cited. The first two are putative, relatively uncontroversial. Paleo-anthropologists and evolutionary geneticists generally agree that two introgression events took place with the direct ancestor of Homo sapiens 700-800,000 years ago, and 300,000 years ago.
Modern African introgression with Homo erectus, Naledi, Australopithecus sediba or other hominin?
Note – Wonkam and Adeyemo neglect to include dates on the chart. But going by the divergence line of Homo sapiens and then Neanderthal, Denisovan, which is 490,000 years ago, it can be easily surmised that the two introgression dates are 700-800,000 years ago, and 300,000 ya.
The divergence date for Africans and Eurasians is generally assumed to be 45,000 to 70,000 years ago. Some paleo-anthropologists and evolutionary geneticists have suggested as high as 90,000 ya.
The third blue line representing another introgression event comes after the divergence between Africans and Eurasians.
Note – the authors use a green line to represent Neanderthal introgression. Therefore they imply that the blue line represents the same species.
Wonkam and Adeyemo do not specify which hominin species is represented by the blue line. Homo erectus (earlier Homo ergaster), would seem to be the only hominin species to fit their criteria. Dates for Homo erectus are from 1.9 million ya to 70,000 ya. (Ref. Smithsonian). But other possible candidates could include smaller brained species such as Australopithecus sediba, Homo naledi and Homo rhodesiensis (Kabwe skull), considered likely related to Florisbad man (Florisbad skull SA).