Milkyway
12-02-2019, 05:33 PM
It seems that the % of Neanderthal ancestry has decreased from 3-6% to 2% in Eurasia (source (https://www.nature.com/articles/nature17993)), and this is somewhat surprising, even considering that a big proportion of the introgressed Neanderthal DNA segments in humans are slightly deleterious.
A study (https://www.pnas.org/content/116/5/1639) explored this issue in depth and found an alternative (and perhaps more plausible) explanation: instead of this dramatic decrease in Neanderthal ancestry what really happens is that present-day West Africans carry moderate amounts (10%?) of European-related ancestry.
In conclusion: Neanderthal ancestry has not decreased in West Eurasia over the last 45,000 years; instead, it has gradually increased in Sub-Saharan Africa over the last 20,000 years due to gene flow from W. Eurasia.
I am not aware if there are studies that support substantial European-related ancestry in West Africans. Is there any data that suggests this migration from W. Eurasia into Africa actually took place?
A study (https://www.pnas.org/content/116/5/1639) explored this issue in depth and found an alternative (and perhaps more plausible) explanation: instead of this dramatic decrease in Neanderthal ancestry what really happens is that present-day West Africans carry moderate amounts (10%?) of European-related ancestry.
In conclusion: Neanderthal ancestry has not decreased in West Eurasia over the last 45,000 years; instead, it has gradually increased in Sub-Saharan Africa over the last 20,000 years due to gene flow from W. Eurasia.
I am not aware if there are studies that support substantial European-related ancestry in West Africans. Is there any data that suggests this migration from W. Eurasia into Africa actually took place?