Understanding Our Evolution through our Mouth Microbes
Neanderthals are the closest ancient relatives to humans, and yet we still understand very little about many of their daily habits, including what they ate. Additionally, researchers don’t understand how these habits contributed to their development and evolution. One of the most puzzling changes that occurred in the Neanderthal body is a doubling in the size of the brain. The growth of the brain would require a diet high in starch and glucose, which is in contrast to the current perception of Neanderthals as mostly meat eaters. Different bacteria that live in our mouths can help us break down different kinds of food. By studying populations of oral bacteria in individuals, researchers can gain clues as to what type of food is most prevalent in their diet.
In a recent study, researchers collected oral bacteria from the teeth of Neanderthals that lived up to 100,000 years ago. They sequenced DNA from these bacteria, and compared them to bacteria in the oral cavities of pre-agricultural humans, chimpanzees, gorillas, and howler monkeys. They found that the Neanderthals and pre-agricultural humans had very similar communities of bacteria. Specifically, both had bacteria that are able to bind to amylase, an enzyme found in human saliva. Because amylase is important in the breakdown of sugar, this means that the bacteria identified likely consumed sugar. The presence of these bacteria on the teeth of Neanderthals and humans suggests that the Neandetherals were eating more starch-heavy foods than previously thought.
The results of this study change our perception of the most common foods that Neanderthals ate. It also may help explain why they were able to grow their brain sizes so significantly. Additionally, this study is an example of how new technologies, such as sequencing and microbiome research, can help us understand ancient questions in evolutionary anthropology.
Lead author James Fellows Yates is a graduate student at the Max Planck Institute for the Science of Human History. Senior author Christina Warinner is an Assistant Professor of Anthropology at Harvard University, a Group Leader of Microbiome Sciences at the Max Planck Institute, and a University Professor of Biological Sciences at Friedrich Schiller University in Jena, Germany.
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