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

WASHINGTON, June 1 (Reuters) – The most comprehensive genetic study ever conducted in primates–a group whose membership includes lemurs, primates, apes and humans–has revealed genetic traits uniquely pivotal to humans while improving the timeline for our lineage’s evolutionary split from ours. Closest cousins, 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 surprisingly discovered that most boast greater genetic diversity — the diversity within species that is vital to adapting to changing environments and other challenges — than humans. .

While some genetic differences previously thought to be exclusive to humans were found in other primate species, researchers identified others 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 primate genetic diversity is not only important in addressing the ongoing biodiversity crisis, but also has enormous potential to improve our understanding of human disease,” said Lucas Cuderna, a genomics scientist from the Barcelona Institute for Biomedical Research in Evolutionary Biology in Spain and Illumina. Inc (ILMN.O), lead author of the lead paper on the research published in the journal Sciences.

There are more than 500 species of primates, including lemurs, lorises, hippopotamuses, 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 traits such as large brains, high dexterity — most species have opposable thumbs — and good vision. They inhabit the Americas, Africa including Madagascar, and Asia,” Kuderna said.

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

The study adjusted the timeline for the difference in the evolutionary lineage that led to humans and that which led to 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 the succession of species, acquired such basic characteristics as bipedalism, longer limbs, and a larger brain. Our species, Homo sapiens, originated approximately 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 in the aftermath of the asteroid strike 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 far more genetic variations per individual than humans,” said genomics scientist and study co-author Jeffrey Rogers of Baylor College of Medicine in Texas. “This 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 in greatest need of conservation efforts.

The study covered some of the most endangered primates. This included the western black-crested gibbon, with an estimated 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 find that genetic diversity is a poor predictor of extinction risk in general,” Cudierna said. “This may be because the numbers of 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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