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....
So what? How does a sequenced gene lead to anything positive?
The short answer is that a sequenced gene should enable cattle breeders to create more productive cattle faster because they will be able to find sires with the correct genetic outputs without having to go through the time-wasting (and expensive) process of actually crossing cows and tracking their production over a lifetime.
Traits carried by bulls are important in determining how much milk a cow produces. Because bulls don't make milk, however, a bull's "performance profile" has to be sketched by observing the milk production of his daughters -- a process that takes about six years and costs $25,000 to $50,000. Now, male calves can be tested at birth for milk-enhancing traits using gene-chip technology.Of course, the great thing about cows and chickens and sheep, is that they actually have a milk, meat, and eggs axis upon which to evaluate the animal.
In the dog world, a true axis for performance is largely gone. You can find it in the world of racing greyhounds, and (arguably) in the world of working terriers, sled dogs, and border collies. But Chihuahuas and Bulldogs, Scotties and German Shepherds?
Not so much.