June 14, 2012
Bonobo Genome Found Strikingly Similar To Humans And Chimps
Lawrence LeBlond for redOrbit.com
The bonobo, one of man´s closest relatives, has had its genome completely mapped by German researchers, placing a new checkmark in the DNA-sequencing list that already includes humans, chimpanzees, gorillas and orangutans, giving scientists a complete record of the great ape genome.
The achievement, published Wednesday in the journal Nature, should help scientists, together with the other great ape genome maps, better understand human evolution. Humans share a genetically close bond with the peaceful, yet little-understood bonobo, as well as the more violent, but better-understood chimpanzee.
Bonobos and humans share 98.7 percent of the same genetic blueprint, the same amount shared between humans and chimps, the study found. The team also found that chimps and bonobos share 99.6 percent of their genomes with each other.
“Humans are a little like a mosaic of bonobo and chimpanzee genomes,” said study lead author Kay Pruefer, a geneticist at the Max Planck Institute in Germany.
Pruefer worked with an international team of researchers to sequence the DNA of Ulindi, a female bonobo at Leipzig Zoo in Germany.
“There´s a common ancestor that we and these apes were derived from. We want to know what that ancestor looked like,” Wes Warren, a geneticist at Washington University in St. Louis, who was not involved in the research, told the LA Times. “By adding the bonobo to the mix, we have a better idea.”
Comparing Ulindi´s DNA, along with a few other bonobos, with the DNA of chimps from different areas of Africa, Pruefer and his colleagues found that bonobos share similar amounts of DNA with all of them. That suggests that the split between chimps and bonobos was rapid and complete, with mating between groups nearly non-existent, noted Pruefer. Otherwise, there would have been a clear sign of genetically similar chimps living nearer to bonobo territories.
Both bonobos and chimps have distinctly different behaviors that are seen in humans. Bonobos are thought of as peaceful, loving creatures, while their closely-related counterparts, the chimps, have been documented to kill and make war, Duke University researcher Brian Hare told the Associated Press (AP). Bonobos share food with complete strangers, whereas chimps do not. Bonobos stay close to their mothers long after infancy, which is similar humans; and chimps use tools better and have bigger brains, also like humans, Hare explained.
Pruefer noted that bonobos, chimps and humans all shared a single common ancestor about 6 million years ago. Chimps and bonobos shared the same common ancestor until about a million years ago, when the Congo River formed, after which bonobos developed on one side of the river, chimps on the other.
Bonobos have slightly smaller heads than chimps, and their teeth are arranged differently. The behavior of bonobos is much more on the tolerant side, being more social, whereas chimps tend to release tension by fighting, said Hare. Bonobos are also ruled by alpha females, while chimps are ruled by males.
Hare told AP reporter Seth Borenstein that bonobos are like a child version of the chimp. “They never grow up and we have lots of data to support this idea. Much of their psychology seems to be frozen.”
Pruefer and colleagues are hoping to learn something about the origin of the behaviors seen in bonobos and chimps, and the degree to which they are influenced by genetics.
“That´s the great hope,” Pruefer told BBC News. “If you look at bonobos, chimpanzees and humans, what you can see is that there are some specific characteristics that we share with both of them.”
“So, for instance, the non-conceptive sexual behavior is a trait that is certainly shared with bonobos, while the aggressive behavior unfortunately is also a trait that is shared with chimpanzees,” Pruefer said. “In a way, it is a question of what the ancestor of all three looked like. Which one actually evolved the new trait here?”
The researchers said they plan to look deeper into those areas of the genome where humans share more similarity to either bonobos or chimps. It turns out that more than 3 percent of the human genome is more closely related to either bonobos´ or chimpanzees´ genome than these are too each other.
“The genome is a resource for further study. You have to go and test the genes,” he said.
And that is just what we plan to do, he concluded.