Ancient Poop Reveals Secrets of Gut Microbe Evolution
If you looked at the picture above and thought “hey, that looks an awful lot like…” you’re right. They say that you are what you eat, but it’s your poop that’s really amazing — at least to archaeologists, who have learned a ton about early human societies thanks to coprolites (fossilized feces) like those above. Fortunately their research material is long-past the odiferous stage; it’s a lot like handling any other rock that’s been around for a while (in fact, some people make coprolite jewelry!). Poop also provides a fascinating glimpse into the workings of the digestive tract, which is its own miniature society with cops, robbers and more.
Many people are familiar with the use of coprolites to find out more about the early human diet. Fossilized feces can tell us what people were eating, even down to which foods members of different social classes and groups ate. Over long periods of time, they can show us which plants and other food sources were living around the area people settled. They can also offer insight into hunting ranges, the domestication of animals and plants, and more. All of this provides a detailed picture of how people lived, what kind of nutritional status they enjoyed, and how they survived in sometimes harsh conditions.
But other researchers are taking an even closer look at coprolites. They’re not as interested in what people were eating as they are in the bacteria that lived in the gut, and analysis of feces from the 14th century is turning up some intriguing information about the complex evolutions of gut bacteria — and how humans have changed in relationship to the contents of their guts.
The bacteria in your gut are a crucial part of healthy digestive function, as you may already know. When you have a healthy balance of gut fauna, they help you digest food, fight dangerous bacteria and keep things moving around at a good pace. They’re also shed in the stool and leave traces of themselves behind. When the balance is disturbed, you can experience symptoms like diarrhea or malnutrition. The composition of gut bacteria can depend on factors like genetics, where you are in the world, what you eat and your medical history, so understanding ancient bacteria provides all sorts of new information about people who lived before us.
In the study of 700-year-old stool, researchers found some fascinating information about the natural antibiotics produced by the body to fight off bad bacteria. Over time, a miniature war has been waged in the human gut: bad bacteria arrive, good bacteria secrete natural antibiotics, bad bacteria evolve to resist them, good bacteria step it up. This back and forth has been a subject of much discussion in some corners of the scientific community. In this find, researchers were able to get snapshots in time of human gut microbe evolution, which can help them trace the history of bacterial evolution.
Might sound like pretty messy, boring stuff, but it could have big implications for science and medicine, where the fight to develop newer, better antibiotics is a real struggle — and where poop transplants are being seriously considered (and FDA approved) for some patients who have lost their gut bacteria!
Photo credit: Tommy.