An article published in the journal “Molecular Biology and Evolution” describes a genetic research on Greenland Inuits. A team of researchers led by Dr. Fernando Racimo of the New York Genome Center used genomic information of about 200 people and comparing them with those of a number of hominids concluded that in particular two key genes for cold adaptation were inherited from hominids called Denisovans or their close relatives.
Genetic research on adaptation of the Inuits were made in recent years. The Inuits are commonly called Eskimos and are one of the peoples who live in the Arctic regions also thanks to some physiological adaptations. In September 2015, an article published in the journal “Science” focused on the genes that make the Inuits better suited to cold and to a diet rich in Omega 3 fatty acids.
Some of the researchers who participated in that research kept on investigating to discover the origins of those genes. To find them, they compared the genomic information of about 200 Greenland Inuits with those collected in the 1000 Genomes Project, a catalog at the genetic variations of homo sapiens, but also to those of other hominids whose DNA was analyzed such as Neanderthals and the ones called Denisovans.
We know very little about the Denisovans because only a few bones belonging to these hominids have been found. However, thanks to progress in genetic analysis techniques, in recent years it’s been possible to analyze their DNA. The results show traces of various crossbreedings with Neanderthals but also homo sapiens and the Inuits could be among their descendants. Denisovans remains were found in Siberia so it’s possible that they were already adapted to cold climates and that the Inuit inherited those adaptations.
At the center of this new research, there are two particular genes, called TBX15 and WARS2, which allow the body to generate heat using a particular type of body fat. The genetic sequence that contains those two genes is compatible with the DNA of the Denisovans and contains important differences from the sequences present in today’s populations and even in Neanderthals. The researchers can’t rule out that those genes were inherited from other hominids whose DNA wasn’t analyzed but they should be closely related to the Denisovans.
The differences compared to other modern humans and Neanderthals were also found in the mechanisms of regulation of those genes. This suggests that those genetic variants altered their regulation through some mechanism still unclear. The tracing of the various mutations and alterations is already difficult within homo sapiens, even more so when other species now extinct must be included in the research.
The results of this research are far from exhaustive but they bring evidence of a crossbreeding between homo sapiens and other species of hominids. That’s consistent with genetic discoveries in recent years that are reconstructing the history of various crossbreedings of this type. We can expect further studies to reveal the presence of genes from other hominids in modern human populations because homo sapiens’ history is turning out to be really complex under this point of view.
