Cattle genes may give clues about human health

By Julie Steenhuysen

CHICAGO (Reuters) - Scientists have created the first genetic blueprint of domestic cattle, saying on Thursday the map may lead to tastier beef, better milk and even new insights about human health.

The Hereford cow's is the first mapped livestock animal sequence, and the researchers think it will help explain how cattle evolved, why they ended up with a four-chambered stomach, and why they almost never get cancer.

"Having the genome sequence is now the window to understanding how these changes occurred," said Harris Lewin of the University of Illinois, who worked on the research published in two reports in the journal Science.

Lewin was part of the Bovine Genome Sequencing Project, an international consortium of more than 300 scientists from 25 countries who worked six years to complete the genetic sequence of the beef cow.

"The mammals we have looked at previously have been laboratory animals and humans," Kim Worley of Baylor College of Medicine in Houston said in a statement. "This is the first mammalian livestock animal we have studied."

They discovered the cattle genome contains at least 22,000 genes, 80 percent of which are shared with humans. And the team found that cattle have far more in common genetically with humans than do mice or rats, and might make better subjects for studying human health.

Comparisons of the domestic cattle genome sequence to those of the human, dog, mouse, rat, opossum and platypus reveal new insights about the human genome.

COWS VERSUS HUMANS

"The most exciting result that we have is the discovery of the really species-specific genome features. Those features of the genome that tell us more of what makes a cow a cow, a horse a horse, a sheep a sheep and what makes a human a human," Lewin said in an audio interview on Science website.

A second group called the Bovine HapMap Consortia traced the history of DNA evolution and domestication of bovines.

They looked at key DNA differences or haplotypes among the bovine family tree, comparing the Hereford sequence to those of six other breeds: the Holstein, Angus, Jersey, Limousin, Norwegian Red and Brahman.

They also did follow-up studies on nearly 500 cattle from 19 geographic and biologically distinct breeds.

In general, they found that present cattle came from a diverse ancestral population from Africa, Asia and Europe that has undergone a recent rapid decrease in population size, most likely because of domestication.

The researchers hope to use this map of genetic diversity to find traits for better meat and milk production.

"This will tell them which livestock will produce superior meat or milk without investing too much money to improve their condition," David Adelson of the University of Adelaide in Australia said.