The new research provided evidence that bonobo species anatomically may be more closely related to human ancestors than the common chimpanzee, by examining the muscular system of bonobos. Earlier studies have proposed this theory at the molecular level, but this study involves comparison of the anatomy of three species for the first time.
Bernard Wood, professor of human origins at the GW Center for the Advanced Study of Human Paleobiology reported that "Bonobo muscles have changed least, which means they are the closest we can get to have a 'living' ancestor."
Previous studies compared DNA between bonobos and common chimpanzees, but this was the first study to compare the muscles of the three species. By studying the physical functioning of muscles of bonobos, the team could reveal that bonobo muscles had changed less than common chimpanzees, indicating that these were more closely related to the human anatomy than common chimpanzees.
Researchers believe that modern human and chimpanzee/bonobo lineages split nearly 8 million years ago, with the bonobo and chimpanzee splitting 2 million years ago. Following this split, both of these apes developed different traits and physical characteristics, despite remaining close to each other geographically. Because of these dissimilarities, researchers have been interested to find out more about what those differences are and how they relate to humans.
Rui Diogo, a lead author, said, “Besides, the study has shown that there is a mosaic evolution of the three species. These include some features shared by humans and bonobos, others by humans and common chimpanzees, and still others by the two ape species. Such a mosaic anatomical evolution may be related to the slightly similar molecular mosaic evolution between the three species revealed by previous genetic studies. Each of the chimpanzees' species shares about 3 percent of genetic traits with humans that are not present in the other chimpanzee species”.
Since bonobos are endangered, the researchers found a rare opportunity to examine seven bonobos from the Antwerp Zoo that had died and were being preserved. The researchers studied the muscles of bonobos and examined how they physically function.
By understanding the differences between human beings and their closest living relatives could lead to discoveries or our understanding of human health.