The list of decoded genes grows longer and more exotic by the month. The first, the human genome, took 15 years and cost nearly three billion dollars. Then came the chimpanzee, dog, rat, honey bee, chicken and cow. Now, spurred on by the computational horsepower and other technological advances made possible by previous breakthroughs, scientists have turned their attention to the pig, stickleback fish, tammar wallaby and egg-laying platypus. Dozens more creatures are in line for genetic blueprinting - in record times and at increasingly lower costs.

In May Utah State University joined the genome rush as the lead institution in sequencing the genome of sheep. USU's agriculture dean and acting provost Noelle Cockett is the principal investigator overseeing a team of scientists at research universities and institutes in the United States, the United Kingdom, Australia and New Zealand. The scientists are funded in part by the U.S. Department of Agriculture.

"Three percent of the total genome will be sequenced by the end of this year," says Cockett, the first scientist to characterize the genetic mutation responsible for the big and profitable rear ends in callipyge sheep. The process is nowhere near as tedious or error-prone as in the early days of the human genome project when each rung of the DNA helical ladder had to be spelled out letter by letter. Scientists have learned shortcuts since then. Now they have the software to construct a library of essential gene bits that can be sequenced a piece at a time and arranged in the right order, from first chromosome to last. Gradually the gaps will be filled in.

An abridged edition of the sheep genome will be posted on the Internet. For a nominal fee animal scientists will be able to purchase the DNA bit associated with parasite resistance, hair density, meat texture or some other trait of interest to breeders in particular markets. "Australians like strong lamb, Americans prefer a less intense flavor that resembles chicken," says Cockett.

The sequencing of the cow genome has already yielded a blood test that identifies a cow's plump, juicy steak potential before it arrives at the feedlot. The stickleback fish project identified the primary gene involved in the production of pelvic fins, a finding that could help biologists better understand how human limbs develop.

That is just the leading edge of the comparative genomics revolution. There are an estimated 1,000 genetic disorders in humans for which cures might be found if the mutations and their off and on switches could be identified in other mammals subject to the same types of diseases. Sheep are especially good surrogates for studying hypertension and other complex genetic disorders in humans. -Jane Koerner