If the chimps in the zoo look surprisingly human we should not be surprised. Our closest living relatives share a "perfect identity" with 96 per cent of our genetic blueprint, according to an international research team.
A consortium of dozens of scientists has prepared the first comprehensive comparison of the human and chimpanzee genomes. Details of their findings are published today in the journal, Nature.
"As our closest living evolutionary relatives, chimpanzees are especially suited to teach us about ourselves," states the study's senior author Robert Waterston from the University of Washington school of medicine in Seattle. The DNA comparison "dramatically narrows the search for the key biological differences between the species", he believes.
The two genetic blueprints are startlingly similar, much as they were expected to be, the research by the Chimpanzee Sequencing and Analysis Consortium indicates. Although chimps (Pan troglodytes) and humans (Homo sapiens) diverged from a common ancestor about six million years ago, the genetic blueprints are still about 99 per cent identical when directly compared. This drops to 96 per cent "perfect identity" when DNA insertions and deletions are taken into account.
The consortium has a chimpanzee named Clint to thank for the DNA sample. Clint is a former resident at the Yerkes National Primate Research Centre in Atlanta, Georgia, in the US, but he died last year from heart failure aged 24.
Just 29 per cent of the genes found in the two genomes produce identical proteins, the study indicated, but many similar genes were found with no more than one unique change.
The findings will tell us less about what makes us human than about how human diseases occur, states Prof Ken Wolfe of the Department of Genetics at Trinity College Dublin. "In the disease field there will be quite a lot to learn here," says Wolfe, a specialist in comparative genetics. "By having the chimp sequence we can look at the ancestral status of the genome."
This in turn should tell us something about the origins of human diseases, he believes. This is particularly true for diseases with multiple genetic causes.
Intriguingly, researchers found classes of genes that are changing unusually quickly in humans and chimps compared with other mammals. They also found several gene groups were evolving more quickly in humans than in chimps. The human genome has more than 50 genes present that are either missing or partially deleted from the chimp genome.