Because we're all a bit Neanderthals
Listen to the voice of the Neanderthals
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When the Neanderthals injured the Sapiens
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The Neanderthals buried the dead and helped the elderly
Is it the Neanderthals' fault if we get fat easily? A study published in Nature Communications suggests that there may be some truth in this statement: in the DNA of our primitive cousins there are particular genetic variants related to the metabolism of fats that are found equal in modern Europeans, but not in Asians. A legacy that could be linked to the way modern populations of European descent put on flab.
The Neanderthal man genome has been sequenced in its entirety by a consortium led by researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, and now the analysis begins to highlight the similarities and genetic differences of us modern Homo sapiens with respect to to our cousins who died out about 30, 000 years ago. Not without first having coupled with our ancestors, as is now proven, and having left traces in our genetic heritage. It is estimated that modern Europeans and Asians (but not Africans, because the crossing took place after our ancestors had already left Africa) retain 1 to 4 percent of Neanderthanium DNA in their chromosomes.
Fats in the brain
In the latest study, Philipp Khaitovich and an international team of researchers analyzed the distribution of Neanderthal genomic variants in eleven African, Asian and European populations. It turned out that Europeans inherited from Neanderthals three times those involved in fat metabolism compared to Asians. An enormous difference, according to Khaitovich: "It is the first time that we observe differences in the concentration of lipids between populations" said the evolutionary biologist, principal author of the study.
The researchers then analyzed tissues of the cerebral cortex of 14 individuals of European, African and Asian descent, as well as the same number of chimpanzees, to try to understand the function of these genetic variants: although probably the Neanderthal genes influence the composition of the whole body fat, the brain is a privileged source because it is rich in fatty acids (and it was also the most readily available tissue through biobanks). They found that Europeans had differences in the concentration of various fatty acids in the brain that were not present in Asians or even in chimpanzees, proving that they are the result of recent evolution.
First an advantage, now a misfortune?
Now it is a matter of understanding what the differences are, and how they could influence physiological functions. The hypothesis is that these genetic variants have constituted an advantage in the ability to adapt to cold climates, probably allowing to accelerate the metabolism and its ability to break down fats to obtain energy.
If this were the case, it could be that this trait, which was an advantage for surviving in the cold winter temperatures of northern Europe, for the Neanderthals and then for our ancestors, has transformed itself, with the very different needs of modern life, into a cancellation. ? Are these genes of Neanderthal origin also part of the present-day epidemic of diabetes and obesity? It could be, the hypothesis is suggestive, but for now it is early to say.
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