Your roommate’s genes may be shaping your gut bacteria

Scientists studying thousands of rats discovered that gut bacteria are shaped by both personal genetics and the genetics of social partners. Some genes promote certain microbes that can spread between individuals living together. When researchers accounted for this social sharing, genetic influence on the microbiome turned out to be much stronger than previously thought. The study suggests genes can affect others indirectly, without DNA ever being exchanged.

source https://www.sciencedaily.com/releases/2025/12/251223043938.htm