for National Geographic News
Scientists have finished sequencing the genome of the rhesus macaque monkey in work they say will enhance medical research in a wide range of areas, including HIV and neuroscience.
The findings will also advance scientists' understanding of primate evolution and what makes humans genetically distinct. (Read a genetics overview.)
An analysis comparing the macaque genome to the already sequenced chimpanzee and human genomes shows that the three primate species share about 93 percent of their DNA. But they have some significant differences among their genes.
"We really want to know what makes us humans—and different from our primate cousins," said Richard Gibbs, director of Baylor College of Medicine's Human Genome Sequencing Center in Houston, Texas.
"This study allows us to observe what has been added or deleted in each of these three primate genomes during their evolution."
Gibbs is the project leader for the Rhesus Macaque Genome Sequencing and Analysis Consortium, an international team of more than 170 scientists from 35 institutions whose findings are published in tomorrow's issue of the journal Science.
The rhesus macaque is the second nonhuman primate, after the chimpanzee, to have its genome sequenced.
Chimps are believed to be the primates most closely related to humans. Compared to the human genome, the chimp genome is only about 1.5 percent different, while the macaque genome is about 7 percent different.
That divergence makes macaques ideal for the evolutionary study of primates, because important features that have been conserved in primates over time can be more easily seen by comparing rhesus monkeys to humans than by comparing chimps to humans.
"In some ways the chimp, which has already been sequenced, is a little too close for us to make easy sense of what the differences are" between humans and other primates, Gibbs said.
"It's a little easier to contrast the macaque with either chimp or human to make sense of what's going on," he added.
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