Identical twins differ at gut level

Courtesy of Science News

Identical twins may share appearances, mannerisms, even clothes — but the microbes living in their guts are anything but the same. By comprehensively sequencing microbial genes in the gut, researchers have found that communities of bacteria in adult identical twins differ dramatically. The findings, that appear in the Proceedings of the National Academy of Sciences, give scientists a deeper understanding of what makes one person’s intestinal bacteria different from another’s.

Bacteria in the intestines spur digestion, manufacture vitamins and keep people healthy; changes in gut bacteria have been linked to irritable bowel syndrome and metabolic disorders. Because of their role in breaking down and absorbing the nutrients from food, gut bacteria may even influence a person’s weight. In the new study, the researchers comprehensively sequenced bacterial genes in stool samples from a pair of identical twins, 26-year-old obese women from Missouri. Since identical twins have nearly identical DNA, any differences between their gut microbial populations would have to be due to non-genetic factors such as diet, disease history or exposure to antibiotics.

The twins were found to have only 17% of the same bacteria. “Diet is probably a huge, huge factor,” says researchers.