September 24 (WNN) — It is much easier to find fresh food today than it was 50,000 years ago. Requires only a few dollars and a story trip to a restaurant or grocery – no cleanup or hunting required.
The relative ease of modern life may explain why a variant of the human growth hormone receptor gene known as GHRd3 is now so rare, according to a new study.
The variant, which first emerged between 1 million and 2 million years ago, was dominant among Neanderthals and Denisovans, as well as the closet ancestors of modern humans. Today, however, the version is much less prevalent.
Its low presence among modern populations is a reflection of technological advances made by humans over the past 50,000 years, new research published Friday in the journal Science Advances suggests.
In the past, GHRd3 probably helped early humans and their relatives survive periods of depletion, but physical conditions have improved dramatically for humans.
The latest genomic analysis reflected this dramatic change.
“Among East Asian populations we studied, where we observed a drastic reduction in this type of frequency from 85% to 15% of the estimated allele frequency during the past 30,000 years,” said study author Omar Gökkumen, an evolutionary biologist at the University of Buffalo. said in the press release.
As their name suggests, human growth hormone receptor genes aid in the reception of human growth hormone, which determines a range of cellular processes related to growth. The genes of such import are usually conserved across species.
But while the variation was common among archaic humans, including many Neanderthal and Denisovan lineages, it has become a common extinction for modern humans.
It’s not that GHRd3A isn’t useful. According to the latest study, the presence of GHRD3 was associated with better survival and health outcomes in children experiencing severe malnutrition. Additional experiments showed that the variants helped the rats manage periods of reduced food access.
“Our study indicates sex- and environment-specific effects of a common genetic variant. In mice, we observed that GHRD3A leads to a ‘female-like’ expression pattern of dozens of genes in the male liver under caloric restriction, Which potentially leads to the observed size reduction,” said study author Marie Saito, an investigator at the Norwegian University of Life Sciences.
“Women, who are already smaller in size, may face negative evolutionary consequences if they lose weight,” said co-author Dr. Ziukian Mu, associate professor of ophthalmology at Buffalo.
“Thus, it is a reasonable and very interesting hypothesis that a genetic variant that may influence the response to nutritional stress has evolved in a gender-specific manner.”
Animals do not release GHRd3A like humans, making it difficult to uncover the rationale behind its deletion among modern humans. Advances in gene editing technology allowed researchers to engineer mouse models without GHRd3A, revealing the effects of the deletion of the variant.
“This is an exciting time to research human evolution, where it is now possible to integrate data from ancient genomes, gene editing technologies and advanced mathematical approaches to tell the human story in all its messy glory.”