A paper on the subject was published today in the new online science and biomedical journal, eLIFE, a joint initiative of the Howard Hughes Medical Institute, the Max Planck Society and the Wellcome Trust Fund.
Studies of the human microbiome have become one of the hottest areas of biological research, said Knight, a scientist in the ongoing National Institutes of Health Human Microbiome Project that has thus far sequenced the microbial mosaic of 300 humans. The number of microbes living on and inside a typical human is about 100 trillion, outnumbering human cells by about 10 to one. And the microorganisms humans carry around -- or don't -- have been linked to a broad spectrum of diseases ranging from malnutrition and obesity to diabetes, asthma and depression, he said.
"There is mounting evidence that exposure to a variety of environmental sources of microbes can affect long-term health, findings known as the 'hygiene hypothesis,' " said Song, a graduate student in CU-Boulder's ecology and evolutionary biology department and first author on the paper. Proposed by British epidemiologist Richard Strachen in 1989, the hypothesis is that children who have had a lack of exposure to bacteria and microorganisms might be more prone to getting sick because many microbes have co-evolved with people to be beneficial.
In the new study, the team found the composition of human bacteria is affected by factors like age and environmental exposure, said Song. "Our skin microbiota in particular seems to be the most malleable by our immediate surroundings, which includes the presence of household pets."
The primary results indicated the family unit had a strong effect on human microbial community composition across all body sites, said Knight. The weakest relationship on body sites was the father-to-infant connection on the
|Contact: Rob Knight|
University of Colorado at Boulder