By David Brown
Washington Post Staff Writer
Friday, April 24, 2009

The genomes of man and dog have been joined in the scientific barnyard by the genome of the cow, an animal that walked beside them on the march to modern civilization.

A team of hundreds of scientists working in more than a dozen countries yesterday published the entire DNA message — the genome — of an 8-year-old female Hereford living at an experimental farm in Montana.

Hidden in her roughly 22,000 genes are hints of how natural selection sculpted the bovine body and personality over the past 60 million years, and how man greatly enhanced the job over the past 10,000.

As with other species, genes governing the immune system, the metabolism of nutrients and social interaction appear to be where much of the evolutionary action has occurred. The result is an animal that lives peacefully in herds and grows large on low-quality food, thanks to the billions of bacteria it carries around.

Selective breeding has exaggerated and spread some of those traits, producing hyper-passive Holsteins and muscle-bound Belgian Blues, and dozens of humpbacked breeds that combine characteristics of both.

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