Microbes effect on development

There is growing evidence that microbes shape the way organisms develop in early embryonic stages and then continue to play a critical role throughout an organisms’ adult life. Even animals that develop in areas that do not contain microbes are thought to eventually need microbes in order to complete postnatal development. Evidence of this is found in studies that have been done on germfree mice. These mice have been bred to lack gut bacteria. The studies have shown that microbes are necessary in postnatal maturation of the intestinal tract, immune system, and parts of the brain.