Un recente lavoro pubblicato su Genome Biology and Evolution, a cui ho dato un mio contributo quale socio Ex-Plora e IsIPU.
https://doi.org/10.1093/gbe/evy233
Abstract:
Although Tibetans and Sherpa present
several physiological adjustments evolved to cope with selective
pressures imposed by the high altitude environment, especially hypobaric
hypoxia, few selective sweeps at a limited number of hypoxia related
genes were confirmed by multiple genomic studies. Nevertheless, variants
at these loci were found to be associated only with downregulation of
the erythropoietic cascade, which represents an indirect aspect of the
considered adaptive phenotype. Accordingly, the genetic basis of
Tibetan/Sherpa adaptive traits remains to be fully elucidated, in part
due to limitations of selection scans implemented so far and mostly
relying on the hard sweep model.In order to overcome this issue, we used whole genome sequence data and several selection statistics as input for gene network analyses aimed at testing for the occurrence of polygenic adaptation in these high-altitude Himalayan populations. Being able to detect also subtle genomic signatures ascribable to weak positive selection at multiple genes of the same functional subnetwork, this approach allowed us to infer adaptive evolution at loci individually showing small effect sizes, but belonging to highly interconnected biological pathways overall involved in angiogenetic processes.
Therefore, these findings pinpointed a series of selective events neglected so far, which likely contributed to the augmented tissue blood perfusion observed in Tibetans and Sherpa, thus uncovering the genetic determinants of a key biological mechanism that underlies their adaptation to high altitude.
Vedi anche qui: https://www.researchgate.net/publication/328360018_Evidence_of_polygenic_adaptation_to_high_altitude_from_Tibetan_and_Sherpa_genomes
