 Why is there so much excitement about the microbiome? Well, it's almost as though we discovered a forgotten organ that weighs about as much as the brain, but has more cells, more genes, and more connections. I'm talking primarily about the gut and the microbes it contains, although microbes all over the body play all kinds of roles in health and disease that we're just beginning to discover. And the reason why is advances in technology. So over the last 15 years, it's a cliche to remind you that DNA sequencing, the computation got about a thousand times cheaper, but DNA sequencing got about a million times cheaper. And it looks like it's plateaued, but it's going to plummet again. So we now know that, for example, microbes determine whether you're 10 times as attractive to mosquitoes as your camping buddies. The microbes on your skin produce different chemicals. They determine how you respond to drugs. And if you're a fruit fly, they even determine who you want to have sex with. We don't know if that's true in humans yet, but maybe it's just a matter of time before we find out. So can microbes help address malnutrition and help feed the world's nine billion? Well, given the many links between microbes and disease and the fact that microbes are so important in digestion, we decided to use these new technologies to try to figure out whether optimizing your microbes can allow you to derive more nutrition from your food. And as I mentioned, microbes have been linked to a large number of diseases, some of which were unsusmentioned and many of which you'll be hearing more about later in this session. So for example, today I can tell if you're lean or obese with 90% accuracy by looking at your gut microbes. On the other hand, you can probably tell without knowing anything about their microbes which of these people is obese, right? But besides being a neat trick, if I try to do this with their human genes, I can only do it with 58% accuracy versus 90% accuracy based on the microbes. So for some things, the microbes may be more important than every gene in your genome. So we can do even more of this stuff in mice, which in addition to being linked to all of these different diseases ranging from colitis to arthritis and even models of depression and autism, we can do experiments in mice we just can't do in humans like raising them gem-free in a bubble with no microbes of their own and then colonizing them with the microbes from somebody and seeing if those microbes have an effect. So this is Jeff Gordon's gem-free facility at Washington University where we're growing the mice in bubbles and then colonizing them first with microbes from another mouse and then with microbes from another human that we think would change how they look and even how they behave. So for example, in the case of obesity, when we take microbes from a fat mouse and put them into these gem-free mice with no microbes of their own, those mice become fat. The reason why it's fascinating, sometimes it's because they derive more energy from the same diet as mice that got the microbes from the lean letimates. Sometimes microbes change their behavior, so they're hungrier, so they eat more. And we can do the same thing across species. So when we take microbes from a fat human, put them into mice, those mice become fatter. However, we can take the microbes from a lean person and design a synthetic microbial community that prevents the mice from gaining this weight. And we can do the same for malnutrition. So with quashier core, a profound form of malnutrition, if you take the microbes from a child with quash, put them into mice, the mice do really badly. They lose 30% of their weight in three weeks. They die if they're untreated. We can rescue them with the same peanut butter-based supplement that's used in the clinic to rescue the children. And so the idea that we could do personalized medicine based not on the human genome where we're 99.9% the same, but on our microbes where you're 90% different from the person sitting next to you is tremendous. And you can place yourself on this microbial map, by the way. So in a project called American Gut, we're bringing this technology to anyone who's interested in signing up. It's a crowd-funded project, and it lets you put yourself on a map defined by the Human Microbiome Project. So here's the map here. We see different regions almost like different continents for different parts of the human body, different regions with health and disease. What we need to do is not just place you on the map, but develop a kind of microbial GPS to tell you where you should be and turn by turn what you need to do in order to get to that healthy state. Make it so easy to use that even our children can use it. You can imagine even a smart toilet that does DNA analysis, or chemical analysis, and delivers the results instantly to your smartphone. And one thing I'll just notice that today in the world, there are more smartphones than there are toilets. Far more people have access to the smartphone technology than have somewhere to do this kind of thing. So I've talked about what comes out the end, but microbes are also critical, for example, in the soil, altering how well crops grow, how much nutrition the plants produce. Critical for food safety in terms of beneficial microbes and leaf surfaces that fight our pathogens. And so the question I have for you is how can we work together to feed the world's 9 billion by feeding around 100 trillion effectively?