[1/5] Gihishamwotzi, 18, an endangered silverback high mountain gorilla from the Sabyinyo family, stands on top of trees inside a forest in Volcanoes National Park near Kinigi, northwest Rwanda, January 9, 2018. REUTERS/Thomas Mukoya/ File Photo
WASHINGTON, June 1 (Reuters) – The most comprehensive genomic study of primates – a group whose membership includes lemurs, monkeys, apes and humans – has revealed key genetic traits uniquely human while refining the timeline for in the separation of our evolutionary lineage from our closest cousins, the chimpanzees and bonobos.
Researchers said Thursday that they sequenced and analyzed the genomes of 233 primate species, which make up nearly half of those alive today, and surprisingly discovered that most boast greater genetic diversity – variation in within a species that is important for adapting to environmental change and other challenges – than humans.
While some genetic variations previously thought to be exclusive to humans have been found in other primate species, researchers have identified others that are uniquely human involving brain function and development. They also used primate genomes to train an artificial intelligence algorithm to predict genetic mutations that cause disease in humans.
“The study of primate genomic diversity is not only important in the face of the ongoing biodiversity crisis, but also has great potential to improve our understanding of human diseases,” says genomicist Lukas Kuderna of Barcelona Biomedical Research Park’s Institute of Evolutionary Biology in Spain and Illumina Inc (ILMN.O), lead author of the main research paper published in the journal Science.
There are more than 500 species of primates, including lemurs, lorises, tarsiers, Old and New World monkeys, the “small apes” – gibbons and siamangs – and the “great apes” – orangutans, gorillas, chimpanzees and bonobos. Lemurs and loris are the least closely related to humans among primates.
“Primates are a diverse order of mammals to which we humans belong, which are characterized by characteristics such as large brains, high dexterity – with most species having opposable thumbs – and good eyesight. They live in the Americas, Africa including Madagascar, and Asia,” said Kuderna.
Chimpanzees and bonobos are the closest genetically to humans, sharing about 98.8% of our DNA.
The study rearranges the timeline for the divergence of the evolutionary lineage that led to humans and the one that led to chimpanzees and bonobos, finding this milestone occurred 6.9 million to 9 million years ago, slightly longer than previously estimated.
The human race, through successive species, developed basic characteristics such as bipedalism, longer limbs and larger brains. Our species Homo sapiens appeared approximately 300,000 years ago in Africa before spreading throughout the world.
The study explored the origins of primates as a group. The last common ancestor of all living primates lived between 63.3 million and 58.3 million years ago during a dramatic evolutionary change after an asteroid strike 66 million years ago that wiped out the dinosaurs and allowed the mammals 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% with declining populations.
“Most primate species have more genetic variation per individual than humans,” said genomicist and study co-author Jeffrey Rogers of Baylor College of Medicine in Texas. “This shows that there were likely many significant population bottlenecks that changed the amount and nature of genetic diversity in ancient human populations.”
Genome data may help identify primate species in greatest need of conservation efforts.
The study covers some of the most endangered primates. These include the Western black crested gibbon, with an estimated 1,500 left in the wild scattered across China, Laos and Vietnam, and the northern sportive lemur, with about 40 left in the wild in a small area of northern Madagascar.
“Interestingly, we found genetic diversity to be a poor predictor of extinction risk overall,” Kuderna said. “This may be because primate populations of different species decline so quickly that their genetics haven’t had time to catch up and show a loss of population size.”
Reporting by Will Dunham, Editing by Rosalba O’Brien
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