And you thought you were alone...

Did you know that we have 10X more bacteria in our gut than cells in our body? That makes me wonder if we are who we think we are. It may be time to rethink the species concept...

Advances in technology usually open doors for the exploration of new and exciting questions and this is certainly the case with advances in genome exploration technology. Thanks to shot-gun sequencing and microarray techniques it is now possible to study the symbiotic interaction between us "higher organisms" and our more numerous cohabitants, the tiny microbes.

Metagenomics, a new and exciting field of research (with an equally catchy name), attempts to study communities of microbes directly in their natural environments (e.g. your gut, your mouth, a patch of dirt, the ocean, etc.). By using modern genome sequencing techniques, metagenomics bypasses the need for lab cultivation of individual species. This is a huge step forward because it is estimated that we have only been able to isolate and culture just 1% of all microorganisms in nature. Metagenomics, thus, offers the chance to identify a wider array of microorganisms than previously possible. This new technology also allows the study of the little buggers in their natural setting (e.g. the complex crevices of your nose) as opposed to the artificial conditions of a petri dish.

This field of study offers so much promise that the National Institutes of Health (NIH), the leading biomedical research funding agency in the U.S., has recently announced a new initiative to probe the human microbiome. This ambitious enterprise, which is part of the NIH's Roadmap for Medical Research, will focus on characterizing the populations that our bodies play host to and their role in health and disease.

But microbial populations are not just important for health. Microbe communities are also responsible for maintaining atmospheric balances of CO2, for supporting the health of crops (and in some cases causing their disease), and many types microorganisms produce potential alternative energy sources such as hydrogen, butanol, and methane. Clearly, (and whether we like it or not) these guys make life on this planet what it is and we have only yet begun to understand how it is they do it.

Interested in learning more? The National Academies has recently published a beautiful educational brochure on metagenomics and the importance of studying microbial communities. This brochure is freely downloadable here, where you can also request hardcopies for educational purposes.

Here are also some recent metagenomics publications:

• Metagenomics of the deep mediterranean, a warm bathypelagic habitat. PLoS ONE
• The Sorcerer II Global Ocean Sampling expedition: expanding the universe of protein families. PLoS Biology
• Metabolomics of a superorganism. J Nutrition
• An obesity-associated gut microbiome with increased capacity for energy harvest. Nature
• Metagenomic analysis of the human distal gut microbiome. Science