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metagenomics: Howard Hughes would freak

zzzz · 2008-10-03T22:18:21+00:00

In reply to: [hr]For the first time, researchers are attempting to identify and analyze the types of bacteria that live within us, in an effort that makes the Human Genome Project look like child's play. Instead of sequencing the genes of one microbe at a time, researchers in a five-year, $125 million NIH effort called the Human Microbiome Project are analyzing entire communities of mixed bacteria at once, in a technique called metagenomics. ...The human body teems with so many microbes that they outnumber our own cells ten to one. Vast schools of bacteria are in us and around us, like fish nuzzling a coral reef. "They are not simply along for the ride," says Stanford University microbiologist David Relman. "They are interacting with us." Yet almost all of them are still unknown to science, since most cannot be grown and studied in the laboratory. In ways mysterious to medicine, this microbial menagerie of fellow travelers in and on us is controlling our health, affecting obesity, cancer and heart disease, among others. At this scale of biogeography, we are the world. As many as 500 species of bacteria may inhabit our guts, like H.pylori. Maybe 500 or so other species make themselves at home in our mouth, where each tooth has its own unique bacterial colony, Dr. Relman recently determined. No one knows how many species we contain in all. This past August, researchers at Kings College London identified yet another new species of oral bacteria between the tongue and cheek. ...The diversity is more than anyone expected. Dr. Segre, who specializes in the study of the skin, found one set of microbial communities thriving in the bend of the typical elbow and an entirely different set of colonies on the average forearm. In all, she identified 113 different kinds of bacteria living in concentrations of about 10,000 per square centimeter on the surface and, just beneath the skin, in densities of one million microbes per square centimeter, she reported last May. In a real sense, the history of all these many microbes is the history of humanity itself. "We are living beings that co-evolved with micro-organisms," Dr. Segre says. Evidence suggests that strains of helicobacter bacteria evolved along with humankind from its beginnings in primitive organisms a billion years ago. Every mammalian species appears to have its own unique variety of these microbes. ...In the U.S. alone, antibacterial products account for about $1 billion in sales annually. It is unclear, though, how long we could survive without each other. [hr] WSJ:The Link