For the second time in as many weeks, a prehistoric human genome has been sequenced. It was only recently that the oldest modern human genome was uncovered. Other researchers have examined the DNA of a different current human genome and have reached similar findings. By 37,000 years ago, the practise of mating with Neanderthals had all but disappeared. Neanderthal DNA fragments that are no longer present in any modern human populations have been discovered by researchers.
At Kostenki-Borshchevo north of the Black Sea, a skeleton was discovered. On an average, every base of the genome was sequenced 2.4 times by the team behind the current work, which does not include Svante Pääbo, who has been a pioneer in ancient genomics. A considerable number of errors and gaps can be expected in the sequence because of this. The conclusions are a little shakier as a result, but this shouldn’t affect their validity.
The migration from Africa to the rest of the world was complicated, according to the results. In contrast to the Siberian modern human skeletons that we’ve examined so far, K-14 shares very few of the DNA variations associated with East Asian populations. K-14 All of this shows that East Asians and Eurasians split off early and may even have taken distinct migrations out of Africa or the Middle East. Native American DNA is absent from K-14, leaving only a Siberian skeleton as the only link to the indigenous peoples of North America.
Despite its geographic origin, K-14 has little in common genetically with modern Europeans, instead showing a strong kinship with other early Eurasian populations. They conclude that it may not even be worthwhile to search for certain affinities. According to the scientists, “instead of inferring a few discrete migration events from Asia into Europe,” they write, “we now have evidence that people in Western Eurasia established a huge metapopulation with gene flow in numerous directions occurring repeatedly and perhaps continually.”
The forebears of Europeans weren’t isolated communities; rather, there was a big pool of Eurasian populations that intermarried on a fairly frequent basis.
What about those prehistoric people that interbred with us? A similar percentage of Neanderthal DNA was found in K-14 and modern human populations, as was found in Siberia earlier this year. In contrast, the average length of Neanderthal DNA was longer, which suggests that there was less time for recombination to muddle these sequences. 54,000 years ago is a very close match to the 60,000-year figure predicted using the ancient Siberian DNA, which the authors used to estimate interbreeding time.
Additionally, the authors looked for ancient skeleton samples with Neanderthal DNA in regions where modern humans don’t have access to that particular gene pool. In the intervening 37,000 years, these sections of Neanderthal DNA have either been chosen against or just lost by coincidence.
There is now a distinct field of competition in the sequencing of ancient genomes. Science rushed to publish this paper while it was still under review, indicating that it was still considered important in light of last week’s publication on the Siberian skeleton. An honest fear is that if more similar results are published, they will no longer be regarded as newsworthy. This is a legitimate concern
But the combined weight of these and other findings may be more significant than most of the earlier discoveries. As more samples are collected, the ancestry of present Europeans remains a mystery, which suggests that the ancestry itself is muddled. It’s possible that Eurasians and Native Americans shared ancestry to some degree, as evidenced by affinities revealed in the Altai skull genome. It now appears that this skeleton is an anomaly due to the addition of extra genomes.
Consequently, in a few decades, textbooks regarding the human exodus from Africa will most likely be developed on the results that surfaced long after the papers which generated headlines were published.
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