Monkey map

Following the completed draft of the human genome sequence, there is renewed interest in the genetic differences between species and, particularly, in what makes us human. In the January 4 Science, Asao Fujiyama and colleagues at the RIKEN Genomic Sciences Center in Japan present a first-generation human-chimpanzee comparative genome map (Science 2002, 295:131-134). They used over 77,000 chimp bacterial artificial chromosomes (BAC) and aligned end-sequences with the human genomic sequence. The BAC clones covered almost half of the human genome. They calculated that the degree of identity with human sequences is about 98.77%. Closer analysis of chromosome 21 provided evidence for several human-specific loci. This map represents a step towards discovering what makes us different from our closest relatives, the apes.