The change in dentition suggests that monkeys took over a niche that apes previously occupied, though whether that was a dietary niche or had more to do with primate life cycle remains to be figured out, she said. “Now it is exactly the opposite: we have only a handful of apes and a whole lot of monkeys.“ “If you go back into the Miocene, it was an ape world with essentially no or very few monkeys,“ Hlusko said. Great ape and Old World monkey mandibles that were part of this study. Today there are 19 monkey genera, while apes have dwindled to only six: humans, chimpanzees, bonobos, gorillas, organutans and gibbons. At the same time, numerous species of apes, which had lived across Africa and southern Europe, began to disappear, and monkeys evolved more lineages. This took place about 8 million years ago, in the Miocene epoch, as Earth began to warm, the Mediterranean Sea dried up and Africa’s thick forests transitioned to grasslands and savannah. When Hlusko and her colleagues looked at how the two newly identified traits changed in primates over the last 20 million years, they noticed an unusual shift in tooth shape at the same time apes began to die out and monkeys to proliferate. The rise of monkeys and the decline of apes Hlusko and her UC Berkeley colleagues – former postdoctoral fellow Christopher Schmitt, now at Boston University, and graduate students Tesla Monson and Marianne Brasil – along with Michael Mahaney of the University of Texas Rio Grande Valley in Brownsville, will publish their analysis this week in the journal Proceedings of the National Academy of Sciences.
We now have to figure out what the genome sequences are that underlie these traits, which will enable us to figure out what caused these evolutionary changes in dentition.“ “We found two inherited traits, but identitying the traits is only the first step. “This shows that we can use the power of evolutionary history to unlock what is going on genetically in animals on whom you can’t experiment, such as humans,“ said study leader Leslea Hlusko, a UC Berkeley associate professor of integrative biology. The measurement data prove that the feature is inherited in a similar way in all primates – humans included – and varies across different species and genera in a way that mirrors the evolutionary relationships worked out earlier by analyzing bones and comparing genes. Once it became clear that the relative lengths of the molars and premolars are an inherited trait much like eye color, the researchers measured these traits in the teeth of other primates, sifting through museum collections around the world. The features were discovered after detailed study of the shapes of molars and premolars inherited by baboons in a long-studied colony at the Southwest National Primate Research Center in San Antonio, Texas. The inherited dental features will also help the researchers track down the genes that control tooth development, assisting scientists intent on regrowing rather than replacing teeth. UC Berkeley paleontologists studied the molars and premolars of baboons to uncover inherited dental traits that can help track primate and human evolution. The threat display of a Hamadryas baboon.
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