By Will Dunham
WASHINGTON (Reuters) – The most comprehensive genomic study ever of primates – a group whose members include lemurs, monkeys, apes and humans – has revealed key genetic traits that are uniquely human while refining the timeline of the separation of our evolutionary lineage from our closest cousins, chimpanzees and bonobos.
Researchers said on Thursday they had sequenced and analyzed the genomes of 233 primate species, including nearly half of those alive today, and surprisingly found that most of them show greater genetic diversity. – variations within a species that are vital for adapting to changing environments and other challenges – than human ones.
While some genetic variations previously thought to be exclusive to humans have been found in other primate species, researchers have identified others that were uniquely human, involving brain function and development. They also used primate genomes to train an artificial intelligence algorithm to predict pathogenic genetic mutations in humans.
“The study of primate genomic diversity is not only important in the face of the current biodiversity crisis, but also has enormous potential to improve our understanding of human diseases,” said genomics Lukas Kuderna of the Institute. of Evolutionary Biology at the Barcelona Biomedical Research Park in Spain and Illumina Inc, lead author of the lead research article published in the journal Science.
There are more than 500 species of primates, including lemurs, lorises, tarsiers, Old and New World monkeys, “little apes” – gibbons and siamangs – and “great apes” – orangutans , gorillas, chimpanzees and bonobos. Lemurs and lorises are the least related to humans among the primates.
“Primates are a diverse order of mammals to which we humans belong, which are characterized by traits such as large brains, great dexterity – most species having 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 about 98.8% of our DNA.
The study adjusted the timeline for the divergence of the evolutionary lineage that led to humans and that which led to chimpanzees and bonobos, finding that this step occurred 6.9 million to 9 million years ago. years, a little longer than expected.
The human line, through a succession of species, subsequently acquired key characteristics such as bipedalism, longer limbs and larger brains. Our species Homo sapiens appeared 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 and 58.3 million years ago during a time of remarkable evolutionary innovation following the asteroid strike 66 million years ago. years that doomed the dinosaurs and allowed mammals to dominate.
Human-related threats such as habitat destruction, climate change and hunting have left around 60% of primate species threatened with extinction and around 75% with declining populations.
“The vast majority of primate species have far more genetic variation per individual than humans do,” said genomics and study co-author Jeffrey Rogers of Baylor College of Medicine in Texas. “This shows that there were likely several significant population bottlenecks that altered the amount and nature of genetic variation in ancient human populations.”
Genomic data can help identify primate species most in need of conservation efforts.
The study focused on some of the most endangered primates. These included the western black-crested gibbon, with around 1,500 remaining in the wild scattered across China, Laos and Vietnam, and the northern sportive lemur, with around 40 remaining in the wild in a small area in northern Madagascar.
“Interestingly, we find that genetic diversity is a poor predictor of extinction risk overall,” Kuderna said. “This could be because primate populations of different species have declined so rapidly that their genetics have not yet had time to catch up and reflect this loss in population size.”
(Reporting by Will Dunham, editing by Rosalba O’Brien)