What makes us human? A study of the primate genome offers some clues

WASHINGTON (Reuters) – The most comprehensive genetic study ever conducted of primates — a group whose membership includes lemurs, primates, apes and humans — has revealed genetic traits uniquely essential to humans, while improving the human pedigree. For the evolutionary division of our lineage from our offspring. Closest cousins ​​are chimpanzees and bonobos.

Researchers said Thursday they sequenced and analyzed the genomes of 233 primate species, comprising nearly half of the species alive today, and found surprisingly most species have greater genetic diversity — diversity within species that is vital for adapting to environments. Other challenges – from the human. .

While some genetic differences previously thought to be unique to humans were found in other primate species, researchers have identified other differences that were uniquely related to brain function and development. They also used primate genomes to train an artificial intelligence algorithm to predict disease-causing genetic mutations in humans.

“Studying the genetic diversity of primates is not only important for addressing the current biodiversity crisis, but also has huge potential to improve our understanding of human disease,” said Lucas Cuderna, a genomics scientist at the Institute for Biomedical Research in Evolutionary Biology in Barcelona. In Spain and Illumina. Inc (ILMN.O), lead author of the lead article on the research published in the journal Sciences.

There are more than 500 species of primates, including lemurs, lorises, hippos, Old and New World monkeys, “small apes” – gibbons and siamangs – and “great apes” – orangutans, gorillas, chimpanzees and bonobos. Lemurs and lorises are the least closely related to humans among the primates.

Primates are the diverse group of mammals to which we humans belong, with characteristics such as large brains, high dexterity—most species have opposable thumbs—and good eyesight. They inhabit the Americas, Africa including Madagascar, and Asia,” Kuderna said.

Chimpanzees and bonobos are genetically closer to humans, sharing approximately 98.8% of our DNA.

The study adjusted the timeline of the evolutionary lineage divergence that led to humans, chimpanzees and bonobos, and found that this milestone occurred between 6.9 million and 9 million years ago, slightly longer than previously expected.

The human race, through a succession of species, acquired such basic traits as bipedalism, longer limbs, and a larger brain. Our species, Homo sapiens, originated about 300,000 years ago in Africa before spreading around the world.

The study explored the origins of primates as a group. The last common ancestor of all extant primates lived between 63.3 million and 58.3 million years ago, during a period of remarkable evolutionary innovation that followed the asteroid impact 66 million years ago that wiped out the dinosaurs and allowed mammals to achieve dominance.

Human-related threats such as habitat destruction, climate change, and hunting have left about 60% of primate species threatened with extinction and about 75% diminished.

“The vast majority of primate species have much more per capita genetic variation than humans,” said genomics scientist and study co-author Jeffrey Rogers of Baylor College of Medicine in Texas. “It shows that there were likely several large population bottlenecks that changed the amount and nature of genetic variation in ancient human populations.”

Genome data can help identify key species most in need of conservation efforts.

The study covered some of the most endangered primates. These included the western black-crested gibbon, with about 1,500 remaining in the wild, scattered across China, Laos, and Vietnam, and the northern sportive lemur, with approximately 40 remaining in the wild in a small area of ​​northern Madagascar.

“Interestingly, we found that genetic diversity is a poor predictor of extinction risk in general,” Cudierna said. “This may be because primates of different species declined so rapidly that their genetics did not have enough time to compensate for this loss in population size.”

(Reporting by Will Dunham; Editing by Rosalba O’Brien)

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