Gut bacteria shaped up by our genes, study finds

A new study has shown that our gut bacteria – gut microbiome to be precise – are shaped up by our genes.

While the microbiome is ever changing and it affects our lifestyles in a number of ways, until now importance of genes wasn’t looked at in great details Now a new study at University of Notre Dame has found a much greater genetic component at play than was once known.

The study has been published in Science, wherein scientists point out that the study is based on data collected over 14 years. Scientists looked at more than 16,000 gut microbiome profiles to determine that there is a greater genetic role in the make up of our gut microbiome; however, this heritability changes over time, across seasons and with age. The team also found that several of the microbiome traits heritable in baboons are also heritable in humans.

Beyond helping us with food digestion, the gut microbiome is also responsible for createion of essential vitamins and assists with training the immune system. This new research is the first to show a definitive connection with heritability.

Previous studies on the gut microbiome in humans showed only 5 to 13 percent of microbes were heritable, but Archie and the research team hypothesized the low number resulted from a “snapshot” approach to studying the gut microbiome: All prior studies only measured microbiomes at one point in time.

In their study, the researchers used fecal samples from 585 wild Amboseli baboons, typically with more than 20 samples per animal. Microbiome profiles from the samples showed variations in the baboons’ diets between wet and dry seasons. Collected samples included detailed information about the host, including known descendants, data on environmental conditions, social behavior, demography and group-level diet at the time of collection.

The research team found that 97 percent of microbiome traits, including overall diversity and the abundance of individual microbes, were significantly heritable. However, the percentage of heritability appears much lower — down to only 5 percent — when samples are tested from only a single point in time, as is done in humans. This emphasizes the significance of studying samples from the same host over time.

The team did find evidence that environmental factors influence trait heritability in the gut microbiome. Microbiome heritability was typically 48 percent higher in the dry season than in the wet, which may be explained by the baboons’ more diverse diet during the rainy season. Heritability also increased with age, according to the study.

Because the research also showed the significant impact of environment on the gut microbiomes in baboons, their findings agreed with previous studies showing that environmental effects on the variation in the gut microbiome play a larger role than additive genetic effects. Combined with their discovery of the genetic component, the team plans to refine its understanding of the environmental factors involved.

But knowing that genes in the gut microbiome are heritable opens the door to identifying microbes in the future that are shaped by genetics. In the future, therapies could be tailored for people based on the genetic makeup of their gut microbiome.

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