WHY INUITS STAND BETTER THE COLD?
- Claudia López Rodríguez
- 21 dic 2016
- 1 Min. de lectura
In the Arctic, the Inuits have adapted to severe cold. After the first population genomic analysis of the Greenland Inuits, two gens TBX15 and WARS2 were secuenced. These are thought to be central to cold adaptation by generating heat from a specific type of body fat, being a candidate for adaptation in the Inuits.
Now, a team of scientists led by Fernando Racimo, Rasmus Nielsen et al. have followed up on the first natural selection study in Inuits to trace back the origins of these adaptations.
To perform the study it was needed to compare the genomic data of 200 Greenlandic Inuits with the DNA from Neanderthals and Denisovans. The results affirm that the Inut variant of the TBX15/WARS2 region is related to Denisovans.
TBX15 is a gene known to affect the human body's response to cold, and is associated with a number of traits related to body fat distribution. The authors speculate that the archaic variant may have been beneficial to modern humans during their expansion throughout Siberia and across Beringia, into the Americas.
The research team also worked to understand the physiological role of the region. They found an association between the archaic region and the gene expression of TBX15 and WARS2 in various tissues, like fibroblasts and adipose tissue. They also observed that the methylation patterns in this region in the Denisovan genome are very different from those of Neanderthals and present-day humans.
This discovery is the second major example; the other being the EPAS1 genomic locus (found in the high altitude adaptation of Tibetans) to be passed on from archaic humans into the modern human gene pool.
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