Geographically isolated human populations often develop unique genetic traits that result from their acclimation to the environment. Unfortunately, these adjustments can also predispose them to certain health problems.
That is the case inuita from Nunavika, living in the north of Canada and adapted to the extreme cold of the Arctic. Your metabolism is ready for it, so you have a diet that is very rich in fat. These features, however, seem to cause a greater prevalence cardiovascular disorders and cerebral aneurysms but in the general population.
In order to find out the genetic origin of these disorders, McGill University in Quebec conducted a genomic analysis of 170 inunit Nunavika, whose results were published in the latest issue of the journal. Proceedings of the National Academy of Sciences (PNAS).
The science group, led by neuroscientist Guy Rouleau, studied variations of DNA called polymorphisms of a single nucleotide, as well as a complete sequence of exon (coding region) of 114 of these individuals.
Differences in lipid metabolism
The results have shown that these inuiti have homogeneous genome and very different from any other present population. This homogeneity increases the risk of certain genetic disorderslike cardiovascular, "explains Sinc Rouleau.
The most prominent genetic variants are found in the paths included in lipid metabolism and gating between the cells. According to the authors, this could be a high-intake diet in Inuit to withstand the extreme cold of northern Canada.
In addition, the researchers found a certain variant OR4C3 gen, associated with increased risk of intracranial aneurysms. In this cerebrovascular disorder, the wall of the brain is very weak and causes dilation. In severe cases, the artery wall can crack and cause cerebral hemorrhage.
On the other hand, the paper also found that the Inuites from Nunavik were closely related to Inuit Greenland and northwest of Sibir, "The results show that these populations have been isolated more than 10,000 years ago," says neuroscientist.
The authors emphasize the importance of this study for understanding the genomes of non-European populations – which are usually not adequately represented in genetic research – in order to offer treatments tailored to their needs. In Nunavik Inuita's case, "the results show the need for providing specific neurological services," says Rouleau.
According to the author, the next step in the research will be to deepen genetic traits that increase the risk of aneurysm and determine which interventions can be designed to reduce this risk.
Sirui Zhou, Guy A. Rouleau, et al, "Genetic architecture and adaptations of Nunavik Inuita". PNAS (July 22, 2019)