RICHMOND, Dec. 05, 2002 -- Biologists heralding the sequencing and mapping of the mouse genome call it an advance certain to accelerate medicine's understanding of how human genes work and sometimes fail.

Nearly two years after the international consortium working on the human genome published its work, several of the same research centers have sequenced the genome of the common house mouse. Their work is described in a series of articles in this week's Nature. The mouse genome is expected to illuminate the function of many human genes because the mouse carries virtually the same set, which can be easily manipulated and studied in the lab.

This new ability to compare genomes - the complete genetic sequence of an organism - combined with science's long experience with mouse genetics, will allow researchers to glean important information about how genes work in humans.

"The mouse genome makes the human genome more clear," said Dr. Sonia Pearson-White, director of the University of Virginia's Transgenic Mouse Core Facility. Biologists such as Pearson-White, who genetically manipulate mice to create "models" of human disease in hopes of finding treatments, will be among the first to feel the impact of the new research.

Mammals have many similar biological functions such as immune response, regulation of cell division and development of major organ systems.

"This is an extraordinary milestone. For the first time we have an opportunity to see ourselves in an evolutionary mirror," said Dr. Eric Lander, director of the Whitehead/MIT Center for Genome Research.

The mouse project found that more than 90 percent of genes associated with diseases such as cancer, diabetes, hypertension and obesity are identical in humans and mice, underscoring the rodent's value in medical experiments.

Geneticists now have "a marvelous opportunity for explaining why the same mutation in different species doesn't cause the same disease," said Dr. Walter Nance, former head of human genetics at Virginia Commonwealth University and an expert in the genetics of deafness.

The draft code of the mouse, 2.5 billion DNA letters long, is about 14 percent smaller than the human's, but each species has about 30,000 genes, according to the papers in Nature.

So far, only 300 genes have been identified as unique to either creature. Comparing the mouse and human genomes has led to the discovery of about 1,200 human genes and 9,000 mouse genes.

In what Pearson-White called one of the key findings, researchers found that about 2.5 percent of the shared genomes, once thought of as genetic junk, do not contain codes for genes. Instead, those sections might be involved in regulating the function of genes, controlling when they're turned on and off, scientists said.

Scientists say the mouse-genome research should have an impact far sooner and even wider than that felt when the human genome was sequenced and mapped.

"The availability of the mouse-genome sequence enormously streamlines the development of such [experimental] models," said Dr. Jolene Windle, who heads VCU's Transgenic Mouse Core Facility.

"I expect faster benefits from the mouse genome in the medical arena than we saw with the human genome," said biophysicist Dr. Karen Duca of the Virginia Bioinformatics Institute.

Even researchers on the periphery of genomics will feel the percolating effects of the mouse project, Duca said. For example, the new research will hasten her attempts to understand the "players" in the early immune response to viruses, such as influenza.

The mouse joins a growing roster of creatures, including humans, fruit flies, baker's yeast and roundworms, to have their genetic code - the chemical "letters," or bases - spelled out and analyzed. Those up next include the rat, cow, chimpanzee, honey bee and dog.

The comparisons these organisms will allow are expected to shed light on evolutionary history and biological diversity. Important areas of the genomes are the ones most likely to have been preserved since the species diverged millions of years ago.

The $58 million public push to sequence the mouse genome began in 1999.


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Published by Public Relations, December 02, 2002