By ANDREW BRIDGES, AP Science Writer
LOS ANGELES (AP) - An international team has completed the most comprehensive map ever of the genetic code of the mouse, an accomplishment that will make the laboratory animal more useful to scientists studying human health and disease.
The map covers an estimated 98 percent of the order of the nearly 3 billion letters that make up the mouse code, or genome.
Two efforts have nearly completed the deciphering of those letters, and the map will serve as an atlas of the genome and allow scientists to zero in on regions of interest. It will also permit scientists to fill in gaps that remain in the deciphering efforts, which remain in draft form.
Details are to appear Monday in the online edition of the journal Nature. The map is available for public review on the Internet.
Humans and mice last shared a common ancestor — probably a small rodentlike mammal — roughly 100 million years ago, but today retain similar-sized genomes and many of the same genes. That makes mice ideal stand-ins for humans in genetic studies.
The function of many human genes, much less the role they play in disease, is unknown.
Creating so-called "knockout mice" — animals whose genetic code has been altered in the lab to either turn on or off certain genes that mice and humans share — allows scientists to understand the purpose of those genes and their role in disease, as well as test therapeutic drugs.
"Now that we have the human sequence, it's trying to interpret what's actually contained in it. A lot of genes in the human we don't have a function for them. If we are able to map them in a model organism like the mouse, we can derive their function by knocking them out," said study co-author Simon Gregory of the Wellcome Trust Sanger Institute in Cambridge, England. The team also included scientists from various research institutes and universities in Canada and the United States.
The map will allow scientists to work on genes in the laboratory that have already been identified by computer analysis of the draft sequence data, said Carol Bult, an associate staff scientist with the Jackson Laboratory in Bar Harbor, Maine.
"The genomic sequence is extremely valuable as a substrate for doing computational methods of gene discovery — having the sequence really speeds up your ability to identify genes and other interesting features. However, once they are identified, you need to jump to a different kind of resource to do biology," said Bult, who is not associated with the study.