Researchers have identified 351 genetic variations that may be associated with whether someone is a night or morning person.
The findings from analyses of about 700,000 people's genomes help advance understanding of the genetic basis of chronotype, or whether people are larks, night owls or somewhere in between, The New York Times reported.
The study in the journal Nature Communications also suggests links between chronotype and mental health.
The researchers found that participants who self-identified as morning people reported a higher level of general well-being, and were less likely to have depression or schizophrenia, The Times reported.
Previous research has suggested that night owls are more likely to have mental health problems.
"Perhaps evening people are constantly fighting their natural clock, which might have unintended consequences farther down the line," said study lead author Samuel Jones, a researcher at the University of Exeter in the U.K., The Times reported.
The genes identified in study play a wide range of roles in the body, the researchers said.
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