Great experiment showing that certain traits and disorders can be passed around adults in a mouse community, and also between mothers and their children -- all through bacterial spread.

Commensal bacteria affect human health far more than we realized.

“We have kept bacteria on one side of a line separating the factors that shape our development — the environmental side of that line, not the genetic side,” said co-senior author Herbert W. Virgin IV, MD, PhD. “But our results show bacteria stepping over the line. This suggests we may need to substantially expand our thinking about their contributions, and perhaps the contributions of other microorganisms, to genetics and heredity.”

Bacteria are most familiar through their roles in harmful infections. But scientists have realized that such bacteria are only a tiny fraction of the bacterial communities that live in and on our bodies. Most bacteria are commensal, which means they do not cause harm and often confer benefits.

Commensal bacteria influence traits such as weight and behavior. But until now, researchers thought the bacteria that exerted these effects were acquired during a person’s life. The study is the first to show that bacterial DNA can pass from parent to offspring in a manner that affects specific traits such as immunity and inflammation. 

The researchers linked commensal bacteria in mice to the animals’ susceptibility to a gut injury. Mice with certain inherited bacteria are susceptible to the injury, which is caused by exposure to a chemical. Female mice pass the bacteria to their offspring, making them vulnerable to the injury. Others carrying different bacteria are less susceptible. 

More about this:

http://sciencedaily.com/releases/2015/02/150216125425.htm