I still remember how my stomach turned when in first year my biology teacher informed the class that we have more bacterial cells in our gut (i.e. our microflora) than there are human cells in our entire body.

It is a little gross, but it forces us to change our understanding of what it means to be human.

At this point geneticists view people as complex ecosystems, because all those microbial cells are a part of what makes up a person. Studying the genetics of the whole (human plus microorganisms) is called metagenomics. But metagenomics is more than just humans and their bacteria. It also applies to studying interactions between microorganisms in the wild.

In future articles I’ll highlight some of the exciting research which is uncovering the important effects that our microflora has on our well-being. For now you can check out the excellent metagenomics pages at the national academies.