What makes us human? Primate genome study offers some clues

Lemurs, monkeys, apes, and humans all belong to the primate family, which has been the subject of the most thorough genomic study to date. This study also clarified the time frame in which our evolutionary lineage diverged from our closest relatives, chimpanzees and bonobos.

Nearly half of the species of primates that are currently alive have had their genomes sequenced and analyzed by researchers, who reported their findings on Thursday. Surprisingly, they found that the majority of these species have higher genetic diversity than humans. Genetic diversity is the variation within a species that is necessary for adaptation to changing environments and other challenges.

The researchers identified genetic changes that were specifically human and involved brain function and development, despite several genetic differences that were previously believed to be unique to humanity being discovered in other monkey species. Additionally, they trained an AI model to detect disease-causing genetic alterations in humans using the genomes of primates.

The lead author of the main research paper that was published in the journal Science, genomicist Lukas Kuderna of the Barcelona Biomedical Research Park's Institute of Evolutionary Biology in Spain and Illumina Inc (ILMN.O), stated that studying primate genomic diversity is not only important in light of the ongoing biodiversity crisis but also has enormous potential to improve our understanding of human diseases.

Lemurs, lorises, tarsiers, Old and New World monkeys, the "small apes" (gibbons and siamangs), and the "great apes" (orangutans, gorillas, chimpanzees, and bonobos) are among the more than 500 species of primates. The primates with the least resemblance to humans are lemurs and lorises.

We humans are members of the complex order of animals known as primates, which includes species with opposable thumbs in the majority of cases, enormous brains, high levels of dexterity, and good vision. They live throughout Asia, Africa, especially Madagascar, and the Americas, according to Kuderna.

The closest living species to us genetically are chimpanzees and bonobos, who have 98.8% of our DNA in common.

The study revised the timing for the split between the evolutionary branches that gave rise to humans and those that produced chimpanzees and bonobos, discovering that this historical event took place 6.9 million to 9 million years earlier than previously thought.

Through a series of species, the human lineage eventually accumulated important traits including bipedalism, longer limbs, and a bigger brain. About 300,000 years ago, in Africa, our species, Homo sapiens, first appeared.

The research looked at the common ancestry of primates. After the asteroid strike that wiped out the dinosaurs 66 million years ago and allowed mammals to take control, the last common ancestor of all living primates lived between 63.3 million and 58.3 million years ago. During this time, amazing evolutionary innovation occurred.

approximately 60% of monkey species are now threatened with extinction by human-related stressors such habitat degradation, climate change, and hunting, and approximately 75% have diminishing numbers.

According to genomicist and research co-author Jeffrey Rogers of the Baylor College of Medicine in Texas, "the vast majority of primate species have significantly more genetic variation per individual than do humans." This demonstrates that the number and type of large population bottlenecks that affected ancient human populations' genetic diversity were probably many.

The primate species that require the most urgent conservation efforts may be determined using the genomic data.

Some of the most threatened primates were the subject of the investigation. These included the Northern Sportive Lemur, with just about 40 living in the wild in a limited region of northern Madagascar, and the Western Black Crested Gibbon, with an estimated 1,500 remaining in the wild dispersed between China, Laos, and Vietnam.

Kuderna noted that, "interestingly, we find genetic diversity to be a poor predictor of overall extinction risk." It's possible that this is happening because the genetic makeup of different species of primate populations hasn't had time to catch up with and reflect the rapid reduction in population size.