You might say that you are more bacteria than you are human. The community of bacteria living in your body, known as the microbiome, outnumbers your own cells (10x) and genes (100x). Without them, you would be very unhealthy. They do things for your body that you can't do yourself -- break down the plant matter you eat, synthesize amino acids and vitamins that your own cells cannot, and help keep invading bacteria at bay.
We are developing an appreciation for the wonderful things these helpful bacteria do for us, but we still don't know very much about them. What does a healthy community of bacteria look like? Does my community have different members than yours? Do different species live in different parts of the body? Does this change over time?
The Human Microbiome Project aims to tackle these questions, and the way they are doing it is to find a lot of very healthy people and take an in-depth look at the composition of their microbiomes. So far, researchers have sampled the bacteria from 242 different healthy individuals -- from 15 sites in the body for men, and 18 sites for women -- at several different times, and sequenced it.
A big accomplishment so far is just figuring out how to standardize procedures to deal with the overwhelming amount of information being generated. Initial results from sequencing these thousands of samples have already shown that the types and abundance of bacteria vary much more between different people than they do within one person over time. They also tried to categorize the bacteria by the functions they might be providing, and found that although the identity of the specific organisms varied between people, the functional pathways the bacteria are involved in were more conserved. And while they identified functions for some of the bacteria, they still don't know what a lot of the of the others do.
This is just a start at understanding the bacterial world within us, and with the number of samples the Human Microbiome Project is looking at, there will certainly be a lot more to learn. Once we know what a healthy community looks like, we will be more equipped to understand what happens to this world in times of disease. (Read more about this new research here).