"Not only does our work shed new light on understanding an important aspect of skin biology, it provides yet another example of how genomic approaches can be applied to study important problems in biomedical research," said NHGRI's Scientific Director Eric D. Green, M.D., Ph.D., who is a co-author of the study. "This also demonstrates what can be achieved through efforts that pull together researchers from across NIH."

NIH recently launched the Human Microbiome Project, a part of the NIH Roadmap for Medical Research, to discover what microbial communities exist in different parts of the human body and to explore how these communities change with disease. In addition to skin and nose, that project is sampling the digestive tract, the mouth, and the vagina.

The skin sites selected for the Science study represent three microenvironments: oily, moist and dry. The oily sites included between the eyebrows, beside the nose, inside the ear, back of the scalp, and upper chest and back. Moist areas were inside the nose, armpit, inner elbow, webbed area between the middle and ring fingers, side of the groin, top fold of the buttocks, behind the knee, bottom of the foot and the navel. Dry areas included the inside surface of the mid-forearm, the palm of the hand and the buttock. Researchers found that dry and moist skin had a broader variety of microbes than did oily skin. Oily skin contained the most uniform mix of microbes.

To look for changes that may occur in the skin microbiome over time, the researchers sampled some volunteers twice, with the samples being taken about four to six months apart. Most of the resampled volunteers were more like themselves over time than they were like other volunteers. However, the stability of the microbial community was dependent on the site surveyed. The greatest stability was found in samples from inside the ear and nose, and the least stability was found in samples from behind the knee.

"Our results underscore that skin is home to vibrant communities of microbial life, which may significantly influence our health," said the study's first author, Elizabeth Grice, Ph.D., who is a postdoctoral fellow at NHGRI.

nihroadmap.nih/hmp/