Who descended from modern humans and ancestors of Neanderthals and Denisovans. New research from the University of California, Los Angeles.
Durvasula and Shankaraman provide complementary lines of evidence for archaic introverts in four populations in West Africa. Image by Bob-Wilder, University of Buffalo.
Contemporaries who have ancestors in Europe, Asia and Oceania carry DNA from two archaic species, Neanderthals and Denisovans, which constitute 1–4% of their genome.
These genetic segments came through introversion in modern humans, the process by which members of two populations and, consequently, hybrid individuals, reproduce with members of the parental population.
Recent studies have shown that, although modern West Africans have no Neanderthal or Denisovana ancestry, they may have had introverts by other old housewives in the past.
In a new study, researchers Arun Durvasula and Sriram Shankaraman of the University of California, Los Angeles compared the DNA of Neanderthal and Denisovan with the genome of 405 individuals from West Africa.
The scientists focused on four contemporary populations in West Africa: Ibadan to Yoruba, Nigeria to Essen, Sierra Leone to Mende and Gambian.
They found differences that could be explained intermittently by an unknown archaic hominid whose ancestors were separated from the human family tree before Neanderthal.
The data suggests that this introversion has occurred relatively recently, or may involve multiple populations of archaic humans, an indication of complex and long-lasting interactions between anatomically modern humans and that of archaic hominids. There may be different populations.
“By combining our results in the West African population, we estimate that the archaic population separated from the ancestors of Neanderthals and modern humans 360,000 years ago.
And subsequent contradictions between the ancestors of current Africans aged 0–124,000 years behind. Their descendants contribute from 2 to 19%, ”said the authors.
Dr. Durvasula and Drs. Sankararaman also investigated the frequencies of the archaic DNA segments to determine whether natural selection could have shaped the distribution of Arctic genetic variants.
“We found 33 loci in Yoruba with an archaic fragment frequency of more than 50% and 37 loci in Mende,” he said.
“Some of these genes are in high frequency in both Yoruba and Yoruba, including NF1 (a tumor suppressor gene), MTFR2 (a gene involved with mitochondrial aerobic respiration in the testicles), HS1717B2 (with hormonal regulation A gene involved) , KCNIP4 (a gene with potassium channels) and TRPS1 TRPS1 (a gene associated with tricorhinofofangles) “.
“Three of these genes have been found for positive selection in Yoruba in previous explorations: NF1, KCNIP4 and TRY1. On the other hand, we did not find high frequencies in MUC7, a previously found gene that disrupts the signature of archaeological introverts.”
The team asks for more analysis of modern and ancient African genomes to reveal the nature of this complex story.
“Signs of introversion have been analyzed in West African populations, which raises questions about the identity of archaic hominids and their interactions with modern human populations in Africa,” the researchers said.
“A detailed understanding of archaic introversion and its role in adapting to different environmental conditions will require the analysis of genomes of ancient and extinct genomes throughout the geographic range of Africa.”
The results were published in the journal Science Advance.