The genome sequence of the endangered golden snub-nosed monkey is reported in a paper published online this week in Nature Genetics. The results further our understanding of dietary adaptation in non-human primates.
The golden snub-nosed monkey from southwest and central China represents a group of monkeys, known as colobines, who primarily eat difficult-to-digest foods, such as leaves and seeds. As an adaptation to this diet, colobines have specialized stomach compartments - similar to cows - that contain bacteria that are able to break down plant compounds normally indigestible by mammals.
Ming Li and colleagues sequenced the genome of the golden snub-nosed monkey in order to better understand how this and related species adapted to their special diet. They found an expansion in the number of genes, relative to other primates, that code for salivary enzymes able to neutralize toxic compounds. The authors also found over 2,000 genes that had evolved rapidly in both golden snub-nosed monkeys and cattle, another mammal with compartmentalized stomach. The authors state that these are likely candidates for genes involved in the adaptation to leaf-eating.
Finally, the authors examined the gut bacteria in the monkeys. While the number of bacterial species was similar to that in humans, the makeup of bacterial types was more similar to that of cattle.