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A couple of new papers about Neanderthals have come out in the prior two weeks that I found particularly interesting. One on the impact of culture with the disappearance of Neanderthals and another on how Neandertal genetic introgression can be attributed to addiction and depression.

By hairymuseummatt (original photo), DrMikeBaxter (derivative work) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

By hairymuseummatt (original photo), DrMikeBaxter (derivative work) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)%5D, via Wikimedia Commons

The first documents a new paper in PNAS suggesting that Neanderthal extinction was due to the cultural superiority of modern humans. The disappearance of Neanderthals has been a conundrum, from diseases, mass murder, inability to adapt to climate change. In this new effort, the researchers report that a model they built suggests it was possible that Neanderthals went extinct because human cultural advantages were so great that it made survival for the less culturally advanced group impossible.

The researchers used a prior computer model that mimic interspecies competition. They then added elements that allowed for taking into consideration cultural and technical abilities. Human culture definitely displaced Neanderthal culture, and cultural advantages from modern humans lead to a positive feedback loop… The more advanced one group became the more dominant they became, and the more dominant they became the more their cultural advantage grew. The researchers suggest that cultural advancement goes hand-in-hand with technological innovation which would have allowed early humans to outcompete Neanderthal for natural resources.

The second paper identifies that propensity for nicotine addiction to multiple genes affecting depression introgressed from Neanderthals. The study, published in Science, concludes that over 135,000 genes are likely to have been inherited from Neanderthals. Additionally, these introgressed genes cause modern humans to be more prone to actinic keratosis, hypercoagulable states that lead to heart attacks, embolisms, or complications during pregnancy, because their blood has a tendency to coagulate easily.

Fig. 2. Neandertal SNPs associate with different phenotypes than matched non-Neandertal SNPs.

Fig. 2. Neandertal SNPs associate with different phenotypes than matched non-Neandertal SNPs. Each bar gives the difference between the number of replicated Neandertal SNP associations with a phenotype group (at a relaxed discovery threshold of P < 0.001) and the number expected from a PheWAS over five sets of non-Neandertal sites matched to the allele frequency of tested Neandertal SNPs. The phenotype distributions were significantly different (chi-squared test, P = 0.017), with more Neandertal SNPs associated with neurological and psychiatric phenotypes than expected and fewer digestive phenotypes. The enrichment and depletion were consistent across all five matched non-Neandertal sets (* indicates P < 0.05 for all five comparisons; binomial test) (11)

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