Microbes, more than DNA, might explain why we’re so different from one another. At least that’s what biochemist Rob Knight says in his TED Talk: “How our microbes make us who we are.”
The microbiome is still a relatively new area of research. It’s only recently that scientists have discovered the role that microbes play in our digestion, immune system, and even our behavior. And, while we all share about 99.9% of our DNA with one another, our microbial makeups are only 10% similar on average.
This diversity is even more remarkable when we look inside an individual person. Knight explains that each region of our body – for example, oral, skin, vaginal, and fecal – harbors an entirely distinct microbial community. As it turns out, these communities are so distinct that the difference between the microbes you’ll find in your mouth and the ones on your skin is bigger than the difference between the ecological community of a coral reef and that of a prairie. “This is incredible when you think about it. What it means is that a few feet of difference in the human body makes more of a difference to your microbial ecology than hundreds of miles on Earth.”
These compositional differences are important. They contribute to a range of health factors, including obesity, heart disease, and even depression in mice. With the Human Microbe Project, Knight and his team are trying to map the microbiomes of as many people as possible. With this information, they can figure out how a certain microbiome contributes to a specific health problem, and how to treat it by altering the bacterial composition with microbes from a healthy donor.
Knight explains, “What we need to do is develop a kind of microbial GPS where we not just know where we are currently, but also where we want to go, and what we need to do in order to get there.”