The chimpanzee and another ape, the bonobo, are humans' closest living relatives. These three species look alike in many ways, both in body and behavior. But for a clear understanding of how closely they are related, scientists compare their DNA, an essential molecule that's the instruction manual for building each species. Humans and chimps share a surprising 98.8 percent of their DNA. How can we be so similar—and yet so different?SO MUCH ALIKE...
Human and chimp DNA is so similar because the two species are so closely related. Humans, chimps and bonobos descended from a single ancestor species that lived six or seven million years ago. As humans and chimps gradually evolved from a common ancestor, their DNA, passed from generation to generation, changed too. In fact, many of these DNA changes led to differences between human and chimp appearance and behavior.
EXAMINE THE EVIDENCE
Matching DNA? Human and chimp DNA is nearly identical when you compare the bands on chromosomes, the bundles of DNA inside nearly every cell. Which two chromosomes are more alike?
BANDING PATTERNS
The light and dark bands on these chromosomes, created by a laboratory dye, reveal similarities and differences among human, chimp and mouse DNA.