Scientists have long suspected that a person’s genetics are involved in shaping how their voice sounds. But knowing which genes are involved — and how they wield their influence — has remained out of reach. Now, what researchers are calling the first large-scale genetic study of human voices has identified mutations in a gene that correlate with higher voice pitch, regardless of a person’s sex. It was published on 9 June in Science Advances1.
Before this study, researchers had pinpointed genetic effects on the voice mainly by identifying mutations that lead to speech disorders in people. But “this is the first time we know of a genetic variant that is really, truly affecting voice pitch” across a large population, says Rósa Signý Gísladóttir, a geneticist and linguist at deCODE Genetics, the genomics company in Reykjavik that carried out the investigation.
A thorough checkup
The human voice is partially shaped by body size and hormones: they are often responsible for why female voices tend to have a higher pitch than male voices. But another factor is genetics.
“It’s common knowledge that voices tend to travel in families,” says Kári Stefánsson, a geneticist and the chief executive of deCODE. Aside from anecdotally observing this hereditary link, researchers have conducted a handful of studies to confirm it, including investigations of twins2,3, in which genetic influences could be separated from environmental ones.
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But determining which genes play a part requires sampling a lot of people — and therefore a lot more leg work. That’s where deCODE comes in. The company, founded in 1996, has mined a vast trove of genetic information from the people of Iceland, making the country a hotspot for genetics research. Because many of the people who live there can trace their family trees back to a small number of ancestors, and because the country has kept detailed genealogical records, it is easier than usual to spot variants and correlate them with traits or diseases.
More than half of Iceland’s adult population has now participated in one of deCODE’s genetic studies, according to the firm’s website. In exchange for free health information, volunteers undergo four hours of intensive observation on everything from their bone density to their mental health, Stefánsson says. “You could basically look at it as an extraordinarily thorough checkup,” he adds.
For the voice-pitch study, deCODE recorded the speech of nearly 13,000 Icelanders, and then compared the frequencies of their voices with its genetic database. The team found that shared mutations in one gene — called ABCC9 — correlated with speaking at a higher pitch, across the age and sex spectrum.
Exactly how genetics is causing this phenomenon isn’t clear, but the team has some hypotheses. Among other things, ABCC9 contains instructions for making an ion channel that helps to ensure the proper functioning of the proteins collagen and elastin. These proteins help tissues in the body to stretch — a must for vocal chords to vibrate.
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Furthermore, the researchers found that people with high-voice-pitch mutations were more likely to have heart conditions. On the surface, this might seem unusual. But it makes sense, the team says, because collagen and elastin help heart muscles to move properly. Too much collagen and faulty elastin can cause heart tissue to stiffen and malfunction. This might also apply to the stretchy parts of vocal chords, Gísladóttir says.
Stefánsson says that he thinks this isn’t the end of the story, and that other genes are probably involved in shaping voice pitch. To find them, though, even more statistical power — volunteers — is needed.
Large-scale genetic studies peering into human voices like this one are “sorely needed”, says Julie Miller, a neuroscientist at the University of Arizona in Tucson. She adds that deCODE’s study shows a nice correlation between ABCC9 mutations and voice pitch, but to prove that the mutations actually cause a higher pitch will require testing in animals.
Gísladóttir is excited by the prospect of exploring this further. The discovery “is truly giving us something new about the biological mechanism of voice that we did not know before”.