Chimps are not like humans

The vigorous debate on how different chimpanzees are from humans is fuelled by new data in this week's Nature, as the International Chimpanzee Chromosome 22 Consortium reports that 83% of chimpanzee chromosome 22 proteins are different from their human counterparts.

The difference is "much more complicated that we initially imagined or speculated," Yoshiyuki Sakaki, who headed the consortium, told The Scientist.

"Our group completed the human chromosome 21 sequence about 3 years ago," Sakaki, director of the RIKEN Genomic Sciences Center, Yokohama City, Japan, told The Scientist. Chimpanzee chromosome 22 is the ortholog of human chromosome 21. Despite being very small, human chromosome 21 contains a number of interesting features, including functional genes, centromere and telomere chromosomal structures, and insertions and deletions including Alu and other repetitive elements, Sakaki said.

"So if we analyze this [chimpanzee] chromosome, we can estimate the overall events that have taken place," Sakaki said.

The ...