"By avoiding inbreeding to produce a diverse population, zoos and conservation groups may be entirely eroding genetic signals specific to certain populations in specific geographic locations in the wild," Sudmant said. One of the captive-bred apes studied by the researchers, Donald, had the genetic makeup of two distinct chimpanzee subspecies, located about 2,000 kilometers away from each other in the wild.
The research also delineates the many changes that occurred along each of the ape lineages as they became separated from each other through migration, geological change and climate events. The formation of rivers, the partition of islands from the mainland, and other natural disturbances have all served to isolate groups of apes. Isolated populations may then be exposed to a unique set of environmental pressures, resulting in population fluctuations and adaptations depending on the circumstances.
Even though early human-like species were present at the same time as the ancestors of some present day great apes, the researchers found that the evolutionary history of ancestral great ape populations was far more complex than that of humans. Compared to our closest relatives, chimpanzees, human history appears "almost boring" conclude Sudmant and his mentor Evan Eicher. The last few million years of chimpanzee evolutionary history are fraught with population explosions followed by implosions demonstrating remarkable plasticity. The reasons for these fluctuations in chimpanzee population size long before our own population explosion are still unknown however.
Sudmant said his interest in studying the great apes, and wanting to preserve great ape species, stems from the similarity of great apes to humans and their curiosity about us.
"If you look at a chimpanzee or a gorilla, those guys will look right back at you," he said, "They act just like us. We need to find ways to protect these precious species from extinction."
