Human adaptation to climate may not be that effective, according to science

New genetic research reveals that humans may be just as vulnerable to climate change as other animals; We didn’t find any major signs evolutionary adaptations until now. Scientists have examined the DNA of more than 1,000 people who have lived in Europe and Asia over the past 45,000 years to find signs of “major sweeps,” when a rare genetic variant takes over a population, and found 50 of them.

Large sweeps usually occur when a change in environmental conditions leads to the extinction of individuals without a more useful genetic variant, such as one that ensures greater protection from the cold: the event is part of Darwin’s Natural Choice. The largest was identified in the Anatolian Farming Community, a genetic region associated with the MHC-III immune system.

Finding hidden genes

Although we have already noticed Scan other types, humans have passed so far. Researchers believe that repeated population mixing over the past 8,000 years has hidden traces of these great genetic events of the past.

One of the main advantages of man lies in cultural innovations, such as fire and clothing, which have helped us conquer the conditions of countless different environments, from tropical forests to tundra. However, it seems that they were not enough to ensure our survival under the pressure of the climatic conditions. Genetic diversity must intervene to allow us to survive.

Individuals with genetic variations that are more beneficial for survival end up having more children, making these genes more common in later generations. In plants and animals, major events in which variations became prevalent are evident from statistical analysis, but in humans they are not. The role of culture or moderate, subtle and hard-to-detect differences were theories that embraced this rarity.

However, with more modern DNA collection techniques, it was possible to begin studying the genomes of populations in Eurasia 10,000 years ago. At that time, at the end of the last Ice Age, there was much greater genetic diversity among humans, most of whom were hunters. They were as different as the modern populations of Western Europe and East Asia.

In the last 8000 years, these differences have been mitigated by several migrations and mixing events, making the population of Europe very homogeneous. Theorizing that this might mask the signs of a large genetic scan, scientists analyzed more than 1,000 ancient genome, after some computer simulations. The oldest genome analyzed was 45,000 years old.

Markers of natural selection showed that ancient DNA contained much greater erase signals than modern DNA, with more recent events more likely to be erased because they were rare or even absent in at least one of the crossbreeding populations. As these events unfold, it becomes clear that we are not much different from other animals in the end.

Large genetic events such as these are found in both humans and other life forms frequently, indicating that they are reasonably common in nature. The adaptations of species to the environment can be better understood by studying their DNA and using statistical methods, according to scientists: until now, we have a biased view of how the forces of environmental stress are adapted.

source: ConversationAnd the Nature’s environment and development

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