When humans entered America 18,000 years ago through the Bering Strait, they encountered a totally different climate and diet. A study recently published in the journal Proceedings of the National Academy of Sciences USA (PNAS) shows that this migration left traces in the genome of Native Americans , descendants of those first settlers. These are genetic variants that facilitate the digestion of fats, a hallmark of adaptation to arctic climates and diets rich in protein. David Comas , scientist at the Barcelona Institute of Evolutionary Biology ( IBE , CSIC-UPF) and director of the Department of Experimental and Health Sciences at UPF who has participated in the research, declares: “The environmental and dietary pressures that found the first settlers of America genetically marked them “. In fact, this is what in evolutionary biology is known as the founder effect .
That is, of the small group of people who Jamaica Email List crossed the strait for the first time, only those who had these mutations that allowed them to survive survived. “As a result, all the populations that arose from these first settlers carry the same genetic variants,” explains Comas. David Comas – IBE The paradox is that the Inuit who live in the Arctic Circle still benefit from this biological adaptation, but the indigenous people of the Amazon, who live in a tropical climate, also retain them. According to Comas, “the fact that current populations contain adaptations from the past is not necessarily negative, but it can lead to metabolic dysfunctions “. These mutations had already been seen in the Inuit, but have now also been found with high frequencies in many of the 53 current and prehistoric populations that have been studied, including tribes from the Amazon and native peoples of North America.
Being in almost all of them, scientists believe that the adaptation happened in an ancestral population, before crossing the strait, and that it was then selected due to environmental conditions. Understanding how natural selection has shaped our current physiology in response to past climate, diet, and disease changes allows us to understand the current genetic makeup of humans in relation to susceptibility to different diseases.which has allowed them to dominate different environments of the oceans for more than 400 million years ”. “Sharkskin is fascinating. It may appear smooth, but seen at a few magnifications it reveals itself as a complex structure, covered by thousands of small denticles known as placoid scales, ”according to Botella. The morphology, body distribution and abundance is what provide relevant information about their way of life.