I couldn’t resist the pun in the title of this post: Metagenomics gets a gut feel. The newly released study behind it, which is having considerable play in the media and on the internet, is the first genetic catalog of the microbes (bacteria, fungi, others) that make up the microbiome (ecosystem) of the human gut. It’s more than a catalog of the wee beasties; it’s also a complete sequencing of the genomes from the most common of the inhabitants. This is the first such massive metagenomics project, where the idea is to analyze and compare the genomes of all the participants in the microbiome.

The work was undertaken by the European Union funded MetaHIT (Metagenomics of the Human Intestinal Tract) project with collaborating research teams in Europe and China. [Source: Nature Magazine: A human gut microbial gene catalogue established by metagenomics sequencing] The scope of the project, the vast amount of data it processed, and its potential impact make this something of a landmark study. It seems that everyone has their favorite (sort of weird science) statistics and information from this study. Here’s a sample:

- 576.6 gigabases of gene sequence
- 3.3 million non-redundant microbial genes
- The human body hosts trillions of micro-organisms, most of which live in our gut
- There are more bacterial cells in our body than our own cells (however, our cells outweigh them)
- 99% of the genes are bacterial, from about 1,150 species
- About 160 species of gut bacteria are shared by all people
- You have lots of co-workers in your gut
- Most of the microbes in the gut are not harmful (when in balance)
- Many of the microbes contribute important chemicals and processes to digestion
- Your gut may actually be telling you something

This last one – Your gut may be telling you something – is one of the more interesting spins. It’s a characterization of the possibility the bacteria in your gut produce enzymes, messenger molecules, and other chemistry that may ‘dictate’ your state of hunger (and for what) and perhaps regulate other ‘feelings’ about your health. I’m sure there will be follow-up research in this area.

However, the more important research, already begun in this study, is a result of comparing the genomic components of this microbiome between people from different locations and health conditions. The study itself involved testing the feces from 124 Europeans and is now being widened to 350 individuals with a variety of obesity and bowel problems. While it showed quite dramatically that most of the microbes in the human gut are shared by all of us, there are significant differences – sometimes by locale, sometime by individuals. Analysis of these differences, especially for medical purposes, should be some of the more important findings developed from the data in the catalog.

During much of human history shamans and doctors have studied our stercoraceous output for signs of disease (and other problems). We’ve come a long way…