Writing Science (EFE).- The woolly mammoth was characterized by its fur and its small ears, these and other features were already genetically encoded in the first specimens, but they were defined over the 700,000 years of existence of the species roaming the the Siberian steppes.
A study by Swedish researchers published today in Current Biology examined and compared the genomes of woolly mammoths, from the earliest to the most modern, with those of living African and Asian elephants to find out what made the earliest ones unique, as individuals and as a species. .
Woolly mammoths had some very distinctive morphological traits, but there are many other adaptations like fat metabolism and cold perception that aren’t as obvious because they’re at the molecular level, explained study first author David Diez of the Center for Paleogenetics. from Stockholm.
The team had the genomes of 23 woolly mammoths that had lived in the last 100,000 years, except for one that corresponds to Chukochya, one of the oldest known, from about 700,000 years ago.
The Chukochya genome
This Chukochya genome made it possible to identify genes that evolved throughout the life of the species, with which it can be affirmed that its specific mutations are unique to woolly mammoths and did not exist in their ancestors, added Love Dalén, also a signatory.
The genome of that first known specimen shared approximately 91.7% of the mutations that caused protein-coding changes in more modern woolly mammoths.
This means that many of the species’ defining traits, including thick fur, fat metabolism, and the ability to sense cold, were likely already present when it first diverged from its ancestor, the steppe mammoth, and were evolving.
The first specimens of woolly mammoth
Early woolly mammoths may have had “larger ears and their wool was different, perhaps less insulating and fluffy than that of later woolly mammoths.” Dalen added.
The study identified a gene with several mutations that may have been responsible for their tiny ears, but also others related to life in cold environments and shared by unrelated living arctic mammals.
Some “highly evolved genes related to fat metabolism and storage are also found in arctic species such as reindeer and polar bears, which means that there is probably convergent evolution of these genes in cold-adapted mammals,” Díez said.
Newer woolly mammoths also carried several immune mutations in T-cell antigens not seen in their ancestor, and the authors speculate that these may have conferred enhanced cellular immunity in response to emerging viral pathogens.
In this study all the genomes were found in Siberia, but the researchers hope to be able to compare them with other North American woolly mammoths in the future.
