If you spent your last road trip staring queasily at the horizon, chances are you might be one of around 33% of people who suffer from motion sickness.
Motion sickness, it turns out, might not just be a matter of willpower and intestinal fortitude. Personal genetics company 23andMe has mined the genomes sequenced from the spit of over 80,000 customers to conduct the first evergenome-wide association study of motion sickness. They discovered that variation in certain genes may predispose a person to the dizziness and nausea thought to result from conflicting sensory signals about whether the body is in motion, or standing still.
Using an online questionnaire, participants self-reported how carsick they get from never (a score of zero) to frequently (a score of three). Variations in single bits of genetic code—also known as single nucleotide polymorphisms, or SNPs—in 35 regions of the genome associated with balance, glucose regulation, and eye, ear, and brain development occurred more frequently in people who scored higher on the carsickness scale.
The many different kinds of motion sickness make it difficult to draw broad conclusions from a questionnaire that specifically examined carsickness, explained motion sickness expert and University of Minnesota professor of kinesiology Thomas Stoffregen.
“People get sick in cars, but they get sick in ships, and they get sick at the movies, and they get sick while they’re playing video games, and they get sick in all kinds of different situations,” he said, adding “the fact that there are some genes that line up with the answers that people gave on these online questionnaires does not, does not, does not in any way imply that the genes are causally related to motion sickness.”
From the genetics perspective, Steven McCarroll, assistant professor of genetics at Harvard Medical School, said that there are very few genome wide association studies that have been conducted on this scale–and is optimistic about future studies that take advantage of the databases collected by companies like 23andMe.
“When I realized that they had studied this common phenotype in 80,000 people it’s clear that they had a lot of statistical power,” he said. “I think that it’s just tremendously exciting that communities can organize over the internet and bring amazing statistical power to a problem that required really large cohorts to answer a question like this.”
The announcement of 23andMe’s results—published in the journal Human Molecular Genetics—comes just days after President Obama announced his $215 million Precision Medicine Initiative, which many hope will use the genetic data collected in databases like 23andMe’s to usher in a new age of genetically guided treatment and therapeutic development.