There are many features that distinguish humans from our ancient primate ancestors. Some characteristics that make humans unique are their ability to stand upright and the large size of their brains. A team of researchers composed of evolutionary anthropologists and geneticists at Duke University has recently added the thickness of teeth enamel as another distinguishing trait that humans possess.
Teeth enamel is the tough outer covering of the tooth and is the hardest tissue in the human body. Enamel is responsible for protecting your teeth from the wear and tear of daily use like chewing and grinding and also protects teeth from harsh temperatures or chemicals.
Ancient dental fossil remains have revealed important clues about the origins of the human species. One way in which dental fossil remains give scientists a glimpse into the past is what they reveal about a species’ diet. The study published in the Journal of Human Evolution looked at four specific genes that are responsible for teeth enamel formation. Then, they looked at variations of those genes among six types of species of primates including humans and orangutans. The researchers found that vegetarian primates like chimpanzees had the thinnest tooth enamel while humans had the thickest tooth enamel. Furthermore, they found that a specific gene for thick enamel formation provided an advantage for survival.
“The fossil record is always the most complete for teeth,” says coauthor Christine Wall, associate research professor of evolutionary anthropology at Duke. “And enamel thickness has long been a key trait used to diagnose fossil hominins and reconstruct their diets and life histories.”
The results of this study ultimately gives us more insight into human species development and begin to form a clearer picture of how natural selection works.
“This study provides the important bridges between morphology, developmental processes, and their underlying genetic regulating mechanisms,” said Timothy Bromage, professor of biomaterials and biomimetics at New York University (who was not involved with the study) “Already the results of the reported work are whittling away the many layers of regulation and evolution of enamel structure.”
Image credit: http://en.es-static.us/upl/2012/04/fossil-skulls.jpg