240 Mammals, and We: A Huge Database We’re Scratching Its Surface

At least 11 searches were published simultaneously Last Thursday, as part of a major international effort to decode the genomes of 240 mammalian species, including us.

the Zoonomia Projectproud of its promoters, Take it to another level Comparative genomics efforts over the past 20 years. It is based not only on decoding the new genome, but on collecting data collected by medical studies as well as through thousands of experiments conducted over two decades on fragments of DNA from different animals. The goal is to point out the mutations that are at the heart of what discriminatesHomo sapiens Of these many are mammalian cousins, but also heart What brings us togetherA lot of things haven’t changed in 100 million years, although we obviously don’t look like a cheetah, or a bat, or a dog, or a whale.

With 11 study researchers Explain that they are “only scratching the surface.” from their huge database. “The truth is that, from an evolutionary perspective, we don’t know as much about mammals as we do about how birds diverged” from their cousins. Recap on NPR Radio Biologist Nicole Foley of Texas A&M University.

The main genes, but they are gone

As for what sets humans apart from other mammals, it’s obviously what’s “new” on the scale of evolution—that is, the mutations that have appeared in the past million years—but surprisingly it’s also what’s extinct: in other words, the genetic sequences found in nearly all other mammals. which have been studied and are no longer in themHomo sapiens.

One search began by identifying 10,000 fragments of DNA found in most mammals but not in humans. The bulk of these changes seem to stick to regions that regulate whether or not a gene should be active (producing this or that protein). Even better, most of these changes are close to genes involved in brain development. responsible team this searchLed by geneticist Stephen Riley of Yale University School of Medicine, he then conducted experiments at the cellular level, trying to figure out which of these missing genetic sequences produced changes. They found 800 of them where the “human” version produced a different result than the “chimpanzee” version, sometimes a completely different result: turning off a gene linked to the human nervous system and thus having an effect in a chain of more than 30 others. Genes, including those involved in myelogenesis, that allow neuronal isolation. And the process is slower in humans than in chimpanzees, without knowing why.

Mutations are strange, but expressive

But there are many other examples where identifying a mutation specific to a behavior that is far from us nonetheless opens windows on ourselves. So, one of the searches It looked at transposable DNA fragments, which are commonly called “jumping genes” because they can change their place in the genome. They seem to be more common in carnivores, like us.

in another place, another search Find out what distinguishes hibernating species. Ultimately, this helped identify the genes responsible for aging. Many hibernating species have exceptional life expectancies. Geneticist Elinor Carlson sums it upof the University of Massachusetts, and co-director of the Zoonomia Project.

By comparing all of these mammals, the researchers were also able to stick themselves out a bit further into the past than might have been expected. It has always been assumed that since mammals “benefited” from the disappearance of the dinosaurs 66 million years ago, an explosion of species diversity followed this moment. gold, one of the searches indicates that diversification was already underway 100 million years ago. That was before the continents separated to evolve into their current forms, isolating the different lineages on different continents.

And some of these scientists believe that we can also, thanks to this data, project ourselves into the future. Thus, a group attempted to derive a predictive model for the species most likely to be infected with the future coronavirus. other offers that we can construct a predictive model regarding the extinction risk of a species, on the basis of its genetic diversity that can, in and of itself, reveal the size of its population in the past.