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.
Although certain genetic variations once believed to be exclusive to humans have been discovered in other primate species, the researchers identified distinctive ones related to brain function and development that are truly unique to humans. Furthermore, they harnessed primate genomes to train an artificial intelligence algorithm capable of forecasting genetic mutations in humans that can lead to diseases.
"Examining the genomic diversity of primates holds significance not only within the context of the ongoing biodiversity crisis but also offers immense potential for advancing our comprehension of human diseases," stated Lukas Kuderna, a genomicist affiliated with the Institute of Evolutionary Biology at Barcelona Biomedical Research Park in Spain and Illumina Inc (ILMN.O). Kuderna, who served as the lead author of the primary research paper published in the journal Science, emphasized the importance of this study.
More than 500 different primates species have been identified, including lemurs, lorises, tarsiers, Old and New World monkeys, the "small apes" (gibbons and siamangs), and the "great apes" (orangutans, gorillas, chimpanzees, and bonobos). Among primates, lemurs and lorises have the least resemblance to humans.
Kuderna explained that primates, a diverse order of mammals to which humans belong, possess distinctive characteristics such as large brains, excellent dexterity (with the majority of species possessing opposable thumbs), and sharp vision. Primates are found across the Americas, Africa (including Madagascar), and Asia.
The closest living species to humans 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 like bipedalism, longer limbs, and a larger brain. About 300,000 years ago, in Africa, our species, Homo sapiens, first appeared.
The study 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.
About 60% of monkey species are now threatened with extinction by human-related stressors such habitat degradation, climate change, and hunting, and about 75% have diminishing numbers.
Genomicist and co-author of the study, Jeffrey Rogers from Baylor College of Medicine in Texas, pointed out that the overwhelming majority of primate species exhibit considerably higher genetic variation per individual compared to humans. This finding suggests the occurrence of multiple notable population bottlenecks throughout the history of ancient human populations, resulting in significant changes in both the quantity and characteristics of genetic variation.
The primate species that require the most urgent conservation efforts can be determined using the genome data.
Some of the most threatened primates were the subject of the study. These included the Northern Sportive Lemur, with only about 40 remaining in the wild in a limited area 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 made an intriguing observation, stating that genetic diversity does not serve as a reliable indicator of overall extinction risk. This phenomenon may be attributed to the rapid decline of primate populations across various species, where the genetic makeup has not had sufficient time to adapt and accurately reflect the consequences of diminishing population sizes.