NEW YORK – Investigators in Iceland, Singapore, and Spain have identified common genetic variants contributing to voice pitch in a speech-focused genome-wide association study conducted in thousands of Icelanders.
The team's findings, published in Science Advances on Friday, provided a look at the physical, cognitive, and physiological features influencing voice pitch, pitch variability, and other voice traits over the human lifespan, along with genetic variants influencing pitch patterns.
"By showing that voice and vowel acoustics are influenced by genetics, we have taken important steps toward understanding the genetics and evolution of the human vocal system," first and corresponding author Rosa Gisladottir, a researcher affiliated with Decode Genetics-Amgen and the University of Iceland, and her colleagues wrote.
Using genotyping profiles and speech recordings for 12,901 Icelandic individuals between the ages of 18 and 93 years, the researchers performed a genome-wide association study searching for variants that tracked with voice pitch and vowel acoustics, focusing on pitch and pitch variation, as well as a measures of acoustic energy concentrations related to vowel sounds known as vowel formants.
"The goal was to learn something new about the genetics of the human vocal system," Gisladottir explained in a Decode Genetics video interview with the study's senior author, Kári Stefánsson, founder and CEO of Decode and a researcher at the University of Iceland.
Gisladottir added that "vocalizations and the voice [are] incredibly important for humans, and yet there is so little that we know about the genetics of voice and speech in humans."
Based on analyses spanning some 39.2 million variants identified through whole-genome sequencing on 63,460 Icelandic individuals, combined with imputation profiles from more than 173,000 genotyped Icelanders, the team highlighted voice pitch-associated common variants in a gene called ABCC9.
ABCC9 codes for a protein known as sulfonylurea receptor 2 (SUR2), the researchers noted, which is a regulatory subunit of a potassium channel involved in curbing tissue excitability, mediating synaptic transmission, secretion of certain hormones, and influencing cardiac and vascular features such as pulse pressure and the area of the ascending aortic.
"The mechanism of ABCC9 action on voice pitch is not yet clear," the authors wrote, noting that ABCC9 ties to pitch may reflect the gene's role in steroid hormone production or may stem from non-hormonal processes related to cardiovascular features such as pulse pressure that impact the voice by influencing vocal fold features or other traits.
More broadly, the team's findings supported the notion that there are small to modest heritable components to voice pitch, pitch variability, and vowel acoustics. But the group also identified speech features that vary and shift alongside other biological features and traits.
When they considered voice features in combination with more than 20,000 other phenotyped traits in the Icelander study, for example, the researchers found that pitch variability tends to coincide with personality-related traits such as openness and verbal ability, while voice pitch shifted in relation to traits ranging from head size to lean muscle mass.
The team also highlighted age-related changes in individuals' voice pitch, which differed in the study's female and male participants. While females showed a yearly, age-related decline in voice pitch that leveled off when they reached about 60 years, for example, male participants appeared to have a steady voice pitch until they reached age 60, followed by an annual increase in voice pitch.
Along with the insights gained so far, the work is expected to spark further efforts to understand the ways that genetic variants can impact the human voice, speech, and other human traits.
"We will continue to investigate the diversity of speech and language like all other aspects of human nature," Stefánsson said in an email.