You see it quoted so often that you’d be mistaken for thinking everyone agrees on the ‘we are all descended from a small group of Africans that left the continent 70,000 years ago’.
It’s something that pleases the liberal media, not something geneticists agree on. Ive seen research items other than these rip into the ‘out of Africa theory’ before.I’d like to point out (ad nauseum) that human remains have been found in China over 100k old, making the date part ridiculous. There are remains of modern humans 162k old in Morocco, and 125k old in Israel.
I recommend a careful read of this link, it’s an extremely thorough hatchet job on the ‘Out of Africa’ theory, showing the evidence against it better than I ever could.
X chromosome evidence for ancient human histories
Eugene E. Harris and Jody Hey*
Diverse African and non-African samples of the X-linked PDHA1 (pyruvate dehydrogenase E1 subunit) locus revealed a fixed DNA sequence difference between the two sample groups. The age of onset of population subdivision appears to be about 200 thousand years ago. This predates the earliest modern human fossils, suggesting the transformation to modern humans occurred in a subdivided population. The base of the PDHA1 gene tree is relatively ancient, with an estimated age of 1.86 million years, a late Pliocene time associated with early species of Homo. PDHA1 revealed very low variation among non-Africans, but in other respects the data are consistent with reports from other X-linked and autosomal haplotype data sets. Like these other genes, but in conflict with microsatellite and mitochondrial data, PDHA1 does not show evidence of human population expansion.
The human RRM2P4 pseudogene has a pattern of nucleotide polymorphism that is unlike any
locus published to date. A gene tree constructed from a 2.4 kb fragment of the RRM2P4 locus
sequenced in a sample of 41 worldwide humans clearly roots in East Asia and has a most recent common ancestor ~2 million years before the present. The presence of this basal lineage exclusively in Asia results in higher nucleotide diversity among non-Africans than Africans. A global survey of a single nucleotide polymorphism that is diagnostic for the basal, Asian lineage in 570 individuals shows that it occurs at frequencies up to 53% in south China, while only one of 177 surveyed Africans carries this archaic lineage. We suggest that this ancient lineage is a remnant of introgressive hybridization between expanding anatomically modern humans emerging from Africa and archaic populations in Eurasia.
Fossil evidence links human ancestry with populations that evolved modern gracile morphology in Africa 130,000 – 160,000 years ago. Yet fossils alone do not provide clear answers to the question of whether the ancestors of all modern Homo sapiens comprised a single African population or an amalgamation of distinct archaic populations. DNA sequence data have consistently supported a single origin model in which anatomically modern Africans expanded and completely replaced all other archaic hominin populations. Aided by a novel experimental design, we present the first genetic evidence that statistically rejects the null hypothesis that our species descends from a single, historically panmictic population. In a global sample of 42 X chromosomes, two African individuals carry a lineage of non-coding 17.5 kilobase sequence that has survived for over one million years without any clear traces of ongoing recombination with other lineages at this locus. These patterns of deep haplotype divergence and long-range linkage disequilibrium are best explained by a prolonged period of ancestral population subdivision followed by relatively recent interbreeding. This inference supports human evolution models that incorporate admixture between divergent African branches of the genus Homo.
*Howard Hughes Medical Institute, Departments of Human Genetics and Ecology and Evolution, and Committee on Genetics, University of Chicago, Chicago, IL 60637
Edited by Henry C. Harpending, University of Utah, Salt Lake City, UT, and approv