That, in turn, should help drug companies searching for a new generation of gene-based medicines. Scientists have already mapped the genomes of a host of lower life forms, including the fruit fly and yeast, but the mouse will be only the second mammal to have its genetic code mapped, after man. The ability to overlay the complete mouse genome on the human one should help tease out the missing genes and provide an insight into the biochemical process triggered by genetic mutations. The process is based on the fact that many of the basic mechanisms that control our bodies have changed little as they have been passed down from species to species through evolution. As a result, scientists can get a good idea of what a newly discovered human gene does by mutating a similar gene in lower life forms.
Comparative genomics is unlikely to stop at the mouse.
Celera and Incyte Pharmaceuticals, a rival in genetic information, are among those busily collecting data on other species. Venter said mapping the genetic blueprint of animals such as the dog, the cat, or the rat would be more useful than sequencing close relatives of man, such as the chimpanzee, because there will be more variations to examine. Already comparative genomics is revealing that humans share a lot more genetic traits with other species than might have been expected. Some of the blocks along the mouse genome that have already been sequenced, for example, are proving impossible to tell apart from the human version. Send it .