A new study investigates how genes and social interactions shape the gut microbiome. Credit: Susanne Clara Bard/Google Gemini/UC San Diego Health Sciences
Your "roommate's" genes could be influencing the bacteria living in your gut, and vice versa, according to a study of rats published in Nature Communications.
The discovery reveals a new way genes and social life intertwine—the exchange of gut microbes that move between individuals. Though genes don’t jump between individuals, microbes can. The study found some genes favor certain gut bacteria and these can spread through close social contact.
For the study, published in, researched examined genetic and microbiome data from 4,000 rates. They identified three genetic regions that consistently influenced gut bacteria, despite differences in rearing conditions across the four cohorts.
The strongest link was between the gene St6galnac1, which adds sugar molecules to the gut’s mucus, and the abundance of Paraprevotella, a bacterium the researchers believe feeds off these sugars. It was found in all four cohorts.
A second region contained several mucin genes, which make up the gut’s protective mucous layer and were linked to bacteria from the Firmicutes group. The third region included the Pip gene encoding an anti-bacterial molecule, and was linked to bacteria in the Muribaculaceae family, common in rodents and also found in humans.
The large size of the cohort allowed researchers, for the first time, to estimate how much of each rat’s microbiome was explained by its own genes and how much by the genes of the other rats it lives with.
The researchers found that the abundance of Muribaculaceae were shaped by both direct and indirect genetic influence. Once these indirect effects were included in a statistical model, the total genetic influence increased by 4 to 8 times for the three new gene-microbe links discovered. The researchers say this may represent only a fraction of the true picture.
By demonstrating that genetic influences can be coupled with gut microbe transmission, the authors of the study paint a new mechanism of action whereby the genetic effects of one individual can ripple through entire social groups, altering the biology of others without changing their DNA.
If similar effects occur in humans, it could mean that genetic influences on human health have been underestimated in large studies. Genes may shape not only an individual’s disease risk, but also the disease risk of others.
The researchers now plan to investigate in detail how St6galnac1 influences Paraprevotella in rats, and what biological chain reactions this triggers in the gut and the whole body.
Data from the Centre for Genomic Regulation/UC San Diego