Science and Medicine

Fighting hypoxia thanks to the genome of Tibetans and Sherpa

5 December 2018 | Written by La redazione

A group of researchers highlighted a number of combinations of genetic variants that would favour survival in environments with low availability of oxygen

Living at 4,000 meters above sea level is not easy for numerous factors: among these, there is certainly the low availability of oxygen, which, at that altitude, is about half of what we find at altitude lower. So how do some populations live in these extreme conditions? The secret of Sherpa and Tibetans could be in their DNA. According to a research conducted by an international team coordinated by the University of Bologna and published on Genome Biology and Evolution.

The research, through the sequencing of the DNA of an individual of ethnic Sherpa and people originating from the Tibetan plateau, has highlighted a series of combinations of genetic variants that would favour survival in environments with low availability of oxygen.

In particular, the research has identified processes that allow greater blood circulation and therefore a greater diffusion of oxygen in the tissues: this is possible for the formation and proliferation of blood vessels more efficient than the common one: this guarantee the normal functioning of the organism even at high altitude. The researchers has used a new approach that combines traditional statistical techniques with a new method based on the analysis of all the networks of genes existing in the human genetic heritage and that takes into account, at the same time, the variations present on the many genes that regulate a specific biological process. "The peoples living on the Tibetan plateau and the sherpa ethnic communities that reside in the high altitude valleys on the Nepalese side of the Himalayas are among the most representative examples of how the human species has been able to adapt to very different environments. A capacity that allowed us to reach every corner of the planet and to survive and thrive even in remote and inhospitable areas ". Marco Sazzini, researcher at the University of Bologna who led the study, said this in a press release from Bologna University. “The analyses made so far - continues Marco Sazzini - had led to identify changes in the Tibetan and Sherpa peoples only in two particular genes, linked to a defence mechanism against the so-called" altitude sickness". This research, on the other hand, has allowed to highlight a polygenic model, which shows how the combination of variants distributed over multiple genes has allowed the evolution of a phenotype as complex as that of high-altitude populations. The presence of this complex of genetic variants - concludes the researcher - makes it possible to transport optimal oxygen in the organism of the Tibetan and Sherpa peoples despite the presence of a quantity of haemoglobin and red blood cells equal to or less than that observed in non-genetically adapted to the high altitude ". Next steps. Research could also be useful in the biomedical field. In fact, this information could allow us to identify therapeutic targets suitable for combating pathologies in which hypoxia is a typical feature of the affected tissues. Among these, to name one, there are also tumours.
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