Humans are bipedal ecosystems that carry such large numbers of microbes that they exceed that of their own cells. Identifying and counting these microorganisms “is like exploring a new unknown planet,” say scientists from theconsortium of the Human Microbiome Project, which after five years of work has made known thegenome sequences of microbes that live in the human bodyin fourteen articles, two of them published by the magazineNature and twelve in the magazinesPLoS. “As with the Human Genome Project a decade ago, the Human Microbiome project aims toserve as the basis for future studies of human health and disease“, says Dirk Gevers, co-author of the articles.
According to the researchers’ calculations, between 81% and 99% of all microorganism genera have already been identified in healthy adults. The samples used in the project were obtained from different areas of the body, includingrespiratory tract, skin, oral cavity, digestive tract and vagina. The donors were 242 healthy individuals aged between 18 and 40 years.
The composition of these communities of microorganisms (microbiota) has turned out to be surprisingly diverse and abundant. Furthermore, microbes can vary not only from one part of the body to another but also from one person to another. For example, individuals from the same community share similar types of bacteria in their saliva. However, the bacteria on the skin are very different between two people who live nearby.
The metagenome of the human microbiome could contain8 million protein-coding genes, that is, 360 times more than the genome of human beings. The challenge is “assigning functions to all of them,” the scientists clarify. Some of these microbes have evolved in tandem with people, helping them survive and improving their vital functions. Others, on the contrary, are linked to diseases.
For nowResearchers have narrowed the microbiome’s “most wanted” list to 119 bacteriathat are present in at least 20% of the research participants. Now they will give priority to the analysis of their genomes to find out? Whether they are friends or enemies, if they resist antibiotics, if they produce toxins or molecules that benefit us …?, As explained by Ashlee Earl, another of those responsible for this scientific milestone .
