Narrator: This is Science Today. When it comes to bacteria residing inside the human body, there's actually a lot of variation from person to person.
Pollard: Even within a city, like within St. Louis and then there are differences between St. Louis and Houston and then other studies have looked in other countries and see differences between people between different countries.
Narrator: Katherine Pollard of the University of California, San Francisco's Gladstone Institutes is part of the Human Microbiome Project — a national consortium composed of about 80 research institutions — which is using advanced DNA-sequencing techniques to identify the thousands of microorganisms that live on humans. Pollard's group focused on microbes within the human gut.
Pollard: So, we all differ in terms of what organism we have in our gut. Quite a bit. And we're only just starting to understand why. It may relate to our diet, for example. It may relate to other aspects of our health. But it's important to look at people from different countries and living different lifestyles. So if we want to see what makes someone sick, we need to understand the normal variation first.
Narrator: For Science Today, I'm Larissa Branin.