About 1 percent of people on the autism spectrum have a mutation on the gene called SHANK3. On one Caribbean island, researchers are discovering that a significant number of the monkey population does, too, opening up a whole new avenue for scientists to study the condition. 

Spectrum, a news site for autism research, sent a reporter out to Cayo Santiago, an island owned by the University of Puerto Rico that’s also known as "Monkey Island." Located just off the eastern coast of Puerto Rico, it’s a primate research center where 1500 feral rhesus macaques, descended from 409 monkeys released by primatologists in the 1930s, can be studied in a natural habitat. It’s also an unlikely new hotspot for autism research, which has rarely been conducted with primates before. As many as one in eight of the island’s macaques have a gene mutation on the autism-linked SHANK3. 

By carefully observing and cataloging the interactions and social networks of the island’s monkeys, researchers like University of Pennsylvania neuroscientist Michael Platt can study how genetics plays into behavioral characteristics. 

As Spectrum reporter Brendan Borrell explains:

In 2013, Lauren Brent, Platt’s former postdoc and field research guru who is now at the University of Exeter in the United Kingdom, reported that a monkey’s social tendencies can be passed down from parent to child. She used techniques developed in human behavioral genetics to collect data suggesting that monkeys with few grooming buddies tend to have specific variants of two genes that govern serotonin levels in the brain. One these genes, TPH2, has been implicated in depression and autism. The more recent discovery of a natural SHANK3 variant is particularly intriguing, because it shows that even the most complex and subtle social behaviors can have a clear genetic signature.

This kind of research in the natural world supports lab work in which transgenic monkeys—engineered with SHANK3 mutations, for instance—can be studied to learn more about the underlying causes of autism. 

Read the whole story on Spectrum

Know of something you think we should cover? Email us at tips@mentalfloss.com.