Ancient Egyptian tombs are adorned with drawings and sculptures of sleek, slender-necked canines with pointy ears and long snouts. Many dog lovers have long thought that two breeds alive today -- the Ibizan hound and the Pharaoh hound -- were direct descendants of these regal companions of the pharaohs.

New research, however, concludes something very different: Both breeds, along with several others that dog aficionados have long believed dated back thousands of years, are actually much more modern animals -- re-creations that were probably produced by breeders.

The findings have sent reverberations though the ranks of dog fanciers, who primp and preen their beloved companions for shows and take great pride in their pedigrees.

"This is clearly going to raise some eyebrows in the Pharaoh hound world," said Greg Witt, vice president of the Pharaoh Hound Club of America. "It goes against our belief system. People are pretty passionate about their dogs. There is going to be disbelief."

The findings come from the first detailed genetic comparison of the genes of purebred dogs. As part of an ambitious effort to identify genes that cause disease in dogs and humans, scientists at the Fred Hutchinson Cancer Research Center in Seattle analyzed DNA collected from 414 dogs representing 85 breeds, including some of the most popular.

Using 96 distinct patterns in the genes called "microsatellites," the researchers compared dogs within breeds, and breeds with one another. In the May 21 issue of the journal Science, the team concluded that almost every breed was surprisingly distinct genetically. They were able to identify each dog's breed by its genes with 99 percent accuracy.

In addition, the researchers found that breeds could be clearly grouped into four distinct clusters based on striking similarities in their genes:

* Ancient dogs.

* Those bred originally mainly as hunters.

* A group with many breeds traditionally used as herders.

* A group with several breeds widely employed as guard dogs.

The most ancient breeds all had Asian and African origins and were the most closely related to wolves, from which all dogs descended. The group includes breeds such as the Alaskan malamute and the Siberian husky, which resemble wolves, but also a diverse array of very different-appearing breeds, such as the Samoyed, basenji, Saluki, Afghan, Lhasa apso, Pekingese, Shar-Pei, Shih Tzu and Akita.

"You would not be surprised that the husky goes with the malamute, and that the Shih Tzu and the Pekingese go together, but you would not necessarily put them all in the same group," said Leonid Kruglyak, a geneticist who helped conduct the research.

Even more surprisingly, that group does not include a number of breeds long thought of as the most ancient, including the Pharaoh hound and the Ibizan hound, despite their striking resemblance to dogs depicted in ancient Egyptian art.

The Norwegian elkhound, which had been thought to date to the Vikings, also turned out to be more modern, meaning it originated during the past few hundred years.

"There are lots of breeds that claim to trace their origins to ancient times," said Elaine A. Ostrander, who led the team. "One of the surprises is sometimes it's true and sometimes it's not. The Afghan hound was in the ancient group, but the Ibizan hound was clearly a re-creation from modern times. For dog aficionados, that's going to be the most surprising thing to come out of this analysis."

Many breeds probably died out because of famines, depressions, wars or other events. Breeders then probably reproduced long-gone varieties by mating animals that had traits similar to those depicted in ancient art. Once they succeeded, they simply continued to breed them together to maintain those traits, the researchers said.

"Somebody was interested in that breed and saw pictures and read the stories and couldn't find any present-day example that could track their line back, and so started breeding dogs that looked similar to what he was going for and produced that dog," Kruglyak said.

Heidi Clevenstine, president of the Ibizan Hound Club of the United States, said she was not troubled by the findings. While she was initially attracted to the breed by its history, she has since fallen in love with the dogs' personality and appearance.

"I think they are beautiful. Where they may or may not come from does not change the fact that I find them beautiful," she said.

But Lisa Puskas, who has written several books on Ibizans, questioned the conclusions, citing archaeological and other evidence supporting the dog's link to ancient Egypt. A more likely explanation for the findings is that the dogs picked up genes over the centuries from interbreeding with more modern breeds, she said.

"I believe the ancient Egyptian animals are very distant relatives, but there was a lot of influence over the years," Puskas said. "Logically to me it makes more sense."

Kruglyak acknowledged that that possibility could not be ruled out.

Another surprise was that German shepherds, which might have been expected to be in the ancient group because of their resemblance to wolves, actually were a much closer match to the cluster of mastiff-type dogs, such as the bull mastiff, the bulldog and the Rottweiler. A third group included herding dogs, such as the collie and the sheepdog, but also some unexpected members, such as the greyhound. The last group included terriers and scent-tracking hounds, such as spaniels, terriers and setters.

One of the most surprising findings was that the breeds in the most ancient cluster are found around the world, said Robert Wayne, an evolutionary biologist at the University of California at Los Angeles who studies dogs.

"They are not just from Asia or the Middle East -- the putative beginnings of domestic dogs," Wayne said. "It's clear that after domestication, they moved rapidly around the world."

Although the findings about breeds may attract the most attention, the researchers said their main motivation was to try to find genes that cause diseases. Because purebred dogs have been bred so carefully, they provide an ideal resource for finding genes associated with illnesses, which could help both the animals and their human companions.

"We know there are a lot of complex diseases out there, and there are a lot of genes that contribute to this in both human and dogs," Ostrander said. "In humans it's hard to study. So we've been studying this in dogs."

Officials at the American Kennel Club and the AKC Canine Health Foundation praised the work, saying it will help breeders, veterinarians and scientists eliminate dog diseases.

"This really is revolutionary in terms of increasing the number of tools available to breeders," the AKC's Patti Strand said. "It really will have a tremendous effect on improving the health of dogs."

New research concludes that Ibizan hounds, long believed to date back thousands of years, are much more modern. This representation of the Egyptian god Anubis bears a resemblance to the Ibizan.