The limitations on the conditions of our lives and the form of our bodies are ultimately dictated by our genes, our DNA. Without as-yet untried genetic modification, humans can’t breath underwater, or fly, without some kind of technological assist. However, discoveries made over recent decades have made it apparent that our genes are more flexible than one might think. We carry a huge number of genes that can serve all kinds of purposes, but that doesn’t mean that all those genes will be expressed, that is that they will have the effect they are supposed to have. The study of variations in the expression of genes is called epigenetics, and it has produced some very interesting results. Identical species subject to different environments will be found to have different genes become activated, responding to the stresses the organisms are experiencing.
Such epigenetic responses have been observed among the Quechua people of the Peruvian Andes (see this link: www.sciencemag.org/...) These indigenous people have lived their lives at very high altitudes for hundreds of generations, and their genes respond in a way to facilitate living in an oxygen-deprived environment.
Researchers studied three different groups of Quechua: (1) Quechua who were born and raised at high altitude; (2) Quechua who were born at high altitude but then moved to low altitude when they were young, and (3) Quechua who were born at low altitude.
The scientists look for an epigenetic process called methylation taking place among particular genes associated with creating red blood cells. It was found that Quechua who who were born at high altitude had high methylation of these genes, regardless of whether they stayed in the highlands or moved to lower altitudes. On the other hand, another gene having to do with the breakdown of sugars was highly methylated only for those Quechua who remained in the highlands, suggesting that this modification required constant exposed to low-oxygen environments. It is somewhat an open question whether epigenetic modifications are permanent or not, but the modification to the gene responsible for producing red blood cells appeared to be permanent.
There is a lot more work and many more environmental differences in which to explore the differences in genetic expression, but it is an exciting first step in understanding genetic response to oxygen levels in humans. There are many more directions in which this research can proceed.
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From indyada:
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