Study shows maternal effects are key to gut microbial development in a wild primate

The bacteria that reside in the human gut, or the gut microbiome, are transmitted to offspring through the milk of nursing mothers. A study of wild geladas, a nonhuman primate that lives in Ethiopia, provides new evidence of clear and significant maternal effects on the gut microbiome even after weaning. The results suggest that the impact of mothers on the offspring's gut microbiome extends far beyond the time the infant has stopped nursing. The research was supported in part by two grants from the U.S. National Science Foundation and published in Current Biology.

A team co-led by Stony Brook University anthropologist Amy Lu and Arizona State University biologists Alice Baniel and Noah Snyder-Mackler came to their conclusions by analyzing one of the largest datasets on gut microbiome development in a wild mammal. A possible explanation is that mothers transfer specific bacteria to their offspring.

"Early life gut microbial development is known to have a large impact on later-life health in humans and other model organisms," said Lu. "Mothers can influence this process."

The team used high throughput DNA sequencing to identify and characterize the bacteria residing in the guts of young geladas. Similar to humans, younger infants had the least diverse microbial communities; these gradually became more diverse as the infants grew older. Changes in the gut microbiome with age reflect changes in infant diet, specifically the switch from consuming milk to consuming more solid foods. The team also found that gut microbes in the offspring of first-time mothers diversified more slowly, suggesting an important way in which maternal effects are manifested in this species.

"It's notable that patterns in gut microbial diversification in geladas are similar to what has been found in humans," said Robin Bernstein, a director of NSF's Biological Anthropology Program. "These results open the door to future investigations into the maternal, evolutionary and ecological drivers of parallels in development of this key system."

Future work will focus on examining how differences in the gut microbiome during infancy influence other aspects of development such as growth, the maturation of the immune system, and the pace of reproductive maturation. Because the team will study the same infants as they age, the researchers expect to link the infant gut microbiome and early-life maternal effects to health, reproduction and survival in adulthood.