Understanding the human microbiome.
The average person harbors roughly 10 times more microbial cells
than human cells. Shortly after birth, all humans develop more microbial
cells, which then aid the metabolism in human cells. This activity in
turn aids the metabolism of the microbial cells. On the basis of this
knowledge, researchers are gathering data to map "the second human
genome" in an effort to identify the genes of our microbial
counterparts. Researchers consider the human microbiome to be a cofactor in diseases ranging from obesity, to inflammatory bowel syndrome, and to
cancers, psoriasis, asthma, autism, type 2 diabetes, and nonalcoholic
fatty liver disease.
Already encompassing tens of thousands of human genes, the
microbiome includes between 5 million and 8 million bacterial genes. The
greatest variety of these genes can be found in the alimentary canal and
the mouth; the least diverse variety can be found in the vagina.
Different species tend to dominate certain areas of the body. Ethnic and
racial background, body weight, and geographic location can affect the
variety of microbial genes in any one person.
(Source: Nature, June 14, 2012.)