The personal genomics company 23andMe has identified 35 genetic factors tied to motion sickness, according to a new study published in the journal Human Molecular Genetics.

In what the company says is the first ever genome-wide study looking at motion sickness, 23andMe was able to determine several genes that may be tied to the nausea associated with movement in a car or on a boat. Motion sickness affects around one in three people, and prior research has suggested that it could be hereditary.

The researchers, who are employed by 23andMe (or have been in the past) and own stock options in the company, used genetic data from more than 80,000 23andMe customers. They found that many of these genetic factors were involved in balance, eye and ear development and the nervous system. Overall, the effect appeared to be stronger in women.

Read more: Genetic Testing Company 23andMe Finds New Revenue With Big Pharma

The study also found links between risk for motion sickness and a greater likelihood of having migraines, morning sickness and vertigo.

It’s still unclear what the actual drivers are, and even if a person has the gene variants linked to motion sickness, it doesn’t mean they will definitely have the condition. Genome-wide association studies like the one performed by 23andMe can only find correlations, but they’re still useful strategies for finding at-risk genes.

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