Mouse genes shed light on human 'book of life'

WASHINGTON (Reuters) -- Researchers rushing to read the billions of letters of code in the human genome are getting a boost from a humble source -- the mouse.

Scientists at Celera Genomics say they are burning the candle at both ends to decipher the genetic code that makes a mouse a mouse, and plan to compare this to the human genome to sort out the most important parts.

They hope to publish their findings later this year, at the same time that publicly funded researchers publish what they have been able to learn about the human genome.

"It would be first analysis -- how many genes are there, how many we have in common with other species," Craig Venter, president and chief scientific officer of Celera, told Reuters in a telephone interview.

Last June, the international Human Genome Project and Celera announced they had finished a rough map of the human genome -- the collection of all our genetic material.

But despite headlines that proclaimed the code had been cracked, this meant they simply had the entire coded message -- not the translation. Scientists do not yet know where all the genes are, or even how many genes there are -- estimates now hover between 50,000 and 80,000.

What they have are 3.1 billion repeats of the letters A, C, T and G -- which stand for the nucleotides that string together to control the production of amino acids, which in turn make up proteins, the basic building blocks of all life.

Finding the genes in all this clutter of letters is not easy. This is where the mouse comes in.

So far, the biggest and most complex creature to have its genome sequenced and analyzed is the fruit fly, Drosophila. It has a surprising number of genes in common with human beings, but scientists wanted something even closer.

As mammals, mice are very close to humans in many ways. They have the standard vertebrate layout -- four limbs and five fingers -- and have the same organs as we do.

Mice are also the favorites of laboratory scientists and have been studied a great deal.

"Basically everything we find in the human genome has a mouse counterpart," Venter said. After finishing sequencing the human genome, Celera turned its banks of sequencing machines to the mouse.

Actually, the company is sequencing bits of several different strains of mice, to get enough material to provide a comparison to the human code. "By layering the mouse genome over the human genome we will know how many genes there are," Venter said.

"It tells you there is stuff in common and then you look at the stuff," Paul Gilman, head of policy planning for Celera, said in a telephone interview. "In looking at the stuff you begin to understand what it does."

This is because any part of the genome that looks the same in mice and humans is likely to control something important.

In any genome, there are the genes, there are regulatory regions that help control the genes, and there is so-called junk DNA that may have important functions but scientists have yet to figure out what they are. For the most part, researchers are looking first to identify the genes.

"Genes have particular structure and that structure is associated with particular functions," Gilman said.

"You can say 'oh, that is an ion channel,' or 'oh, that is a secreted protein like insulin' or 'oh, we don't know what this one is."'

Celera says it is far ahead of the Human Genome Project -- a collection of academic and government labs around the world headed by the U.S. National Human Genome Research Institute (NHGRI) -- in sequencing and analyzing the human genome.

The two sides had clashed over publishing their findings but are now cooperating, Venter said. "We agreed it would be good to have simultaneous publication to keep the temperatures down and help people focus on what that means for society," he said.

Copyright 2000 Reuters. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Quick breakthroughs from human genome project
September 12, 2000
The promise and perils of the human genome
June 27, 2000
U.S., Britain urge free access to human genome data
March 14, 2000

Human Genome Project
National Human Genome Research Institute (NHGRI)
Human Genome Links

Note: Pages will open in a new browser window

External sites are not endorsed by CNN Interactive.