Neanderthal DNA sequences may be more common among Africans than previously thought, a study published on January 30 in the journal Cell found. Deeply rooted D0 African Y chromosomal haplogroup, but various non-African populations have more of it than their African counterparts. The researchers also found an over-representation of Nigeria’s genetic ancestry compared to enslaved people who were shipped there from regions of modern-day Nigeria.
Based on these characteristics, the research team concluded that Neanderthal ancestors were introduced back into the African population by the migration of ancient Europeans back to Africa. The researchers were therefore able to identify Neanderthal ancestors among Africans for the first time and convincingly prove that Europeans and Asians possess more than the same amount of them as previously described.
The results also suggest that African genomes contain Neanderthal sequences in greater numbers than those of Europeans and Asians, and in other parts of the world. Moreover, there now appears to be as many Neanderthals as Homo sapiens in Africa and Asia, and as many as one-third of all human genomes in Europe and the rest in Asia and Latin America. Moreover, up to two-thirds of Homo sapiens “human genome sequences now appear to be among African and Asian populations.
Although sub-Saharan Africa is among the most genetically diverse in the world, many of the region’s inhabitants have had a similar lineage since widespread migration began about 2.5 million years ago. Non-Africans represent a diminished subset of diversity in Africa, and not a single human migration from Africa has become the ancestor of non-Africans. A paper this year also argues that migration from southern Africa to East Africa preceded larger movements from – out of – Africa. Africa and ventured west to the Middle East, Asia and Latin America, but not to Europe and Asia.
Genetic studies also support the idea that the earliest spread of modern humans from Africa began about 220,000 years ago. About a third of the DNA comes from ancestors who were hunters – gatherers in West and Central Africa and hunters in East Africa. Compared to the DNA of all modern Africans, this genome is more closely related to that of people from East and Central Africa (sometimes known as pygmies) than to Bantu-speaking populations. While research suggests that other species of hominins may have existed in sub-Saharan Africa as early as 2.5 million years ago, it also suggests that this mix occurred before, and not after, the ancestors of today’s modern Eurasians left Africa.
An alternative theory, however, suggests that the hominins migrated from Africa 2.5 million years ago after Homo ergaster evolved.
The current “African origin” model assumes that modern non-African populations are essentially descended from populations of H. sapiens that left Africa at that time. The lineages occurring in Africa and outside Africa are found in the Middle East, Asia, Europe, North Africa and South America.
The earliest humans to live 6.2 million years ago came entirely from Africa, and the fossils, which bear a diverse mix of H. sapiens, Homo erectus, and other species, appear to have been scattered throughout Africa, from the 260,000-year-old remains of the Floris bath in South Africa to the 195,000-year-old Omo remains from Ethiopia and those that remain in Morocco.
Perhaps one of the most exciting discoveries we can make about African Americans is the identification of the areas of Africa to which our ancestors were brought, including possibly descendants of a common ancestor living in a common homeland. There are no records of ships from the slave era to this day that correspond to the presence of H. Sapiens fossils in East Africa, not in Southern Africa. This suggests that the vast majority of Africans today were born in or near East Africa, not South Africa, in the US and other parts of Europe and Asia.
This finding supports the idea that our modern human ancestors migrated and evolved simultaneously to different parts of the world. It is still believed that some people who do not live in Africa today actually derive from this expansion – from Africa – but not all. The discovery of H. sapiens fossils in East Africa suggests that modern humans have a common ancestor in this region, although some of us still believe that they are actually derived from expansion from Africa.
Previously, it was estimated that the ancestors of modern humans split from the lineage that gave rise to Neanderthals and Denisovans around 700,000 years ago, and diverged from each other about 400,000 years ago. This analysis provides the first evidence that the divergence of the ancestors of modern humans occurred before the separation of Neanderthals and modern humans. Later studies estimated the presence of a second, younger ancestor, called the Y chromosome of Adam, who could also be traced back to Africa.
The Nama sample is the only sample in southern Africa where we have proven an East African ancestry of Namas and Maasai. We have also identified the Y chromosome of a second, younger ancestor of modern humans, the Denisovans, from the same region.