A study appearing in the journal Microbiome find that mothers' genes can influence the bacteria that take up residence in their babies' guts.
Researchers from the University of California, Davis, led by David Mills focused in particular on the fucosyltransferase 2 (FUT2), or 'secretor' gene, which is inactive in many people, though active in others. They also note that the members of the Bifidobacterium genus, which are common infant gut commensal bacteria, are known to eat the 2'-fucosylated glycans found in the breast milk of mothers with active FUT2 genes.
These bacteria also, first author Zachery Lewis at Davis tells NPR, have a role in preventing infections as they lower the pH of the gut, which many pathogens don't like.
In this study, Mills, Lewis, and their colleagues examined how the secretor status of mothers affected the development of their infants' microbiomes. From this, they found that bifidobacteria became established earlier in the gut microbiomes of infants breast-fed by such mothers as compared to infants of non-secretor mothers.
"I think it's exciting how just a single gene is enough to change the baby's microbiome," Lewis says. "It shows that establishing the microbiome is an intricate process, orchestrated by the breast milk."
He notes that other factors influence the makeup of the gut microbiome, and that the breast milk of non-secretor mothers isn't any less healthy or valuable.