Rat Genome Sequencing Consortium Achieves Milestone

The Rat Genome Sequencing Consortium has announced the successful production of one genome's worth of rat DNA sequence, a significant milestone in the effort to sequence and analyze the laboratory rat.

"We now have more than three billion bases of raw rat DNA sequence," said Dr. Richard Gibbs, director of the Baylor College of Medicine Human Genome Sequencing Center. "It is an important milestone in the overall work achieved so far."

Current estimates suggest that the rat genome is composed of three billion base pairs, about the same as the human and mouse genomes. Statistically, this means consortium scientists have identified the components of about two-thirds of the rat genome.

The rat genome, like the human genome, is made up of long strands of the chemical deoxyribonucleic acid, or DNA, organized on chromosomes. DNA itself is made up of chemical subunits called nucleotides, and it is the order of the four types of nucleotides - adenine, thiamine, cytosine and guanine - that determine the function of a gene.

By comparing the genomes of different organisms, scientists can identify genome regions that play a pivotal role in the production of proteins as well as the corresponding regulatory regions, which have been conserved over evolutionary time.

"The ability to compare multiple mammalian genomes with well-developed genetics and disease models will be essential for unlocking the secrets of the human genome," said Doug Smith of Genome Therapeutics Corp.

All of the rat sequence data is being made publicly available, with new results released weekly at the National Center for Biotechnology Information Web site.

"I'm pleased with the progress so far," said Dr. Francis S. Collins, director of the National Human Genome Research Institute. "The rat sequence will help elucidate the instruction book of this important model organism of human diseases, and it will help us understand the human genome, identify new genes and make rapid progress in diagnosing and treating diseases."

In a relatively short time, the consortium has produced a large amount of data, dwarfing the total amount of rat genome sequence previously available.

"The teamwork among the members of the consortium has been extraordinary," said Dr. George Weinstock, co-director of Baylor's sequencing center. "The collaboration and effort of all members of the consortium demonstrates the interaction between public and private sector at its best."

"We can now begin a serious analysis of the rat genome, and are confident that the rat will serve as an important model for how to decipher a mammalian genome," Dr. Gibbs said.

The consortium includes the following research organizations: Baylor's Human Genome Sequencing Center; Celera Genomics Group of the Applera Corp., Rockville, Md.; the Genome Therapeutics Corp., Waltham, Mass.; the British Columbia Cancer Agency in Vancouver; The Institute for Genomic Research, Rockville, Md.; the University of Utah, Salt Lake City; and the Medical College of Wisconsin, Milwaukee.

The consortium received a $58 million grant in February from the National Heart, Lung and Blood Institute and the National Human Genome Research Institute to expand the ongoing work needed to produce a draft sequence of the rat genome within two years.

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©2006 Texas Medical Center

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