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Chimp and Human Chromosomes Are Compared

By Kate Ruder

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Chimps
Evolution

Scientists in Japan have completed the DNA sequence of a chimpanzee chromosome and lined it up alongside its human counterpart to identify genetic similarities and differences. This is the first time that sequenced chromosomes from the two species have been compared.

Chimpanzees are our closest genetic relatives, and the chromosome sequences match up remarkably well. More than 98 percent of the DNA on chimp chromosome 22 is present on human chromosome 21.

The researchers found nearly 68,000 stretches of DNA that were different between the two species, including DNA that had been added to or deleted from one of the chromosomes over the course of evolution. They do not yet know what effects these changes may have had on the biology of humans or chimpanzees.

“In total there are so many different changes that have taken place that it is much more complex than we originally imagined,” says Yoshiyuki Sakaki of RIKEN Genomic Sciences Center in Yokohama, Japan, who led the project.

Sakaki and his colleagues sequenced chimpanzee chromosome 22 using DNA from three healthy male chimpanzees with West African origins. RIKEN had sequenced human chromosome 21 in 2000 as part of the Human Genome Project.

“People are fascinated by human origins, but it is too early to tell whether we’re going to get immediate insights into the things that people are most interested in,” says Maynard Olson of the University of Washington in Seattle.

“In searching for the basis of the physical variation between chimpanzees and humans, differences in genome sequences are just the first place to start: we need to know what these differences mean,” writes Jean Weissenbach of Genoscope, France, in a perspective that accompanies the paper in Nature.

American scientists have completed a draft of the chimpanzee genome and made it available to researchers worldwide via the Internet. They are expected to publish findings from a comparison of the human and chimp genomes later this year.

For more news see GNN’s Chimpanzee Page.

Watanabe, H. et al. DNA sequence and comparative analysis of chimpanzee chromosome 22. Nature 429, 382-388 (May 27, 2004).
Weissenback, J. et al. Differences with the relatives. Nature 429, 353-354 (May 27, 2004).

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