On the Trail of the Cat, Scientists Find Surprises
Monday, March 17, 2008
If cat owners know anything about their pets, it's how enigmatic the creatures can be. But scientists have begun to pull back the feline veil, using the latest molecular tools to get a peek at their origins.
"Cats are certainly more mysterious and complex than we would ever think," said Leslie A. Lyons, who studies cat genetics at the School of Veterinary Medicine at the University of California at Davis. "However, we're starting to get their story."
In one of the most comprehensive explorations of cats' origins to date, Lyons and her colleagues spent about five years collecting feline DNA, poking behind the whiskers of more than 1,100 Persians, Siamese, street cats and household tabbies around the world to swab inside their mouths. The genetic samples came from 22 breeds of fancy cats, mostly in the United States, along with an assortment of feral and pet cats in Korea, China, Kenya, Israel, Turkey, Vietnam, Singapore, Sri Lanka, Tunisia, Egypt, Italy, Finland, Germany, the United States and Brazil.
By analyzing 39 genetic signposts in the samples, the researchers were able to investigate a variety of questions, including which breeds are most closely related and where they most likely originated.
The first thing the group did was confirm a report published last June in the journal Science that the domestication of cats about 10,000 years ago appeared to have occurred in an area known as the Fertile Crescent, which stretches from Turkey to northern Africa and to modern-day Iraq and Iran.
"Our data support the Fertile Crescent, specifically Turkey, as one of the origin sites for cats," said Lyons, who published her findings in the January issue of the journal Genomics. "Turkey was part of the Fertile Crescent and hence was one of the earliest areas for agricultural development."
Cats probably started living close to humans when people evolved from nomadic herding to raising livestock and crops and started storing food, which attracted mice and other rodents. Cats found good hunting there, and humans surely appreciated the sly little predators' help protecting their stocks.
"There was a mutual benefit," Lyons said. "There was a food source of mice and rats all around the grain. So it was beneficial for both cats and humans as the cats came closer to human populations and kind of domesticated themselves."
From there, domesticated cats started to radiate out to different parts of the world, often following humans on their migrations. Today cats can be divided genetically into four broad groups: those from Europe, the Mediterranean, East Africa and Asia.
But Lyons and her colleagues also made surprising discoveries about individual breeds. "We wanted to see whether breeds actually came from what was thought to be their geographical origins," Lyons said.
The Japanese bobtail, for example, does not seem genetically similar to cats from Japan, indicating the breed may have originated elsewhere. "Either it didn't originate in Japan or there's been so much Western influence that they have lost their initial genetic signal," Lyons said.
Despite its name, the Persian, the oldest recognized breed, looks as though it actually arose in Western Europe and not Persia, which today is Iran.