Black Wolves: The first genetically modified predators?

Black wolves: The first genetically modified predators? 14/02/2009 22:53:00 news/2009_jan/black_wolved_nps In playful pursuit, a gray wolf pursues its sibling of a different coat color across their winter territory in Yellowstone National Park. Credit Daniel Stahler/National Park Service. Rise of dark-coloured Canis lupus credited to human dog breeding, may aid in coping with climate change February 2009. Emergence of black-coloured wolves is the direct result of humans raising dogs as pets, according to new research by a University of Calgary biologist published in the academic journal Science. And dark colouring may also aid the survival of the species as wolf habitat is affected by climate change in the future, the study suggests. "Although it happened by accident, black wolves are the first known example of wolves being genetically-engineered by people," said Marco Musiani, an internationally-recognized expert on wolves and a professor in the U of C's Faculty of Environmental Design. "Domestication of dogs has led to dark-coloured coats in wolves, which has proven to be a valuable trait for wolf populations as their arctic habitat shrinks," Musiani said. "It also shows that human activities can help enrich the genetic diversity of wild animal populations, which is a very unexpected finding." "We usually think of domestication as something that is carried out to benefit humans," said Stanford genetics professor Greg Barsh, MD, PhD. "So we were really surprised to find that domestic animals can serve as a genetic reservoir that can benefit the natural populations from which they were derived. It's also fascinating to think that a portion of the first Native American dogs, which are now extinct, may live on in wolves." Canine geneticists generally agree that North American dogs today are all descended from European dogs. Barsh and graduate student Tovi Anderson collaborated with, among others, scientists at the University of California-Los Angeles, the University of Calgary, the National Park Service at Yellowstone National Park and the National Human Genome Research Institute to conduct the research, which will be published on Feb. 5 in the journal Science. Scientists from Sweden and Italy also participated in the international effort. Equally diverse in pelage phenotype, Yellowstone National Park's Druid Peak Pack represents a closely kin-structured group of parents, offspring, and siblings typical of wild wolf packs. Credit Daniel Stahler/National Park Service Equally diverse in pelage phenotype, Yellowstone National Park's Druid Peak Pack represents a closely kin-structured group of parents, offspring, and siblings typical of wild wolf packs. Credit Daniel Stahler/National Park Service Anderson and her collaborators compared DNA collected from 41 black, white and gray wolves in the Canadian Arctic and 224 black and gray wolves in Yellowstone National Park with that of domestic dogs and gray and black coyotes. Their intention was to build on previous work in the Barsh lab that identified a mechanism controlling pigmentation in dogs that differs from most other mammals. "We expected this to be a short research project to confirm that wolves and dogs shared the same genetic pathway that determines black coat color," said Anderson. "But the story got much more interesting when we expanded our research and began asking about the origin of the mutation in wolves." Gray wolf populations Using genetic analysis of gray wolf populations from North America and Europe, the researchers traced the source of the dominant gene responsible for dark coat colour in wolves to domesticated dogs and conclude the trait was passed to the gray wolf population, as well as to coyotes, by mating between the closely-related wild and domestic canid species. The transition could have taken place as recently as the arrival of European domestic dogs in North America or as long as 14,000 years ago when humans migrated into North America across the Bering Strait. Better colour for non-snow conditions Since then, black fur has become commonplace in wolf packs, perhaps because snow-covered northern environments are shrinking and darker colouring allows for greater stealth while hunting in areas without snow. While gray wolves can be found in colours ranging from white to gray to black, light-coloration is predominantly found in the Arctic tundra where wolves prey on barren ground caribou. The researchers note that the relationship between coat colour and habitat is often attributed to adaptation and natural selection, but this is the first example of a genetic modification that probably arose due to human selection becoming adaptive and selected back in nature. White & black wolves. No Gray wolves "I have spent a lot of time in tree-line areas at the southern edge of the tundra and it has always surprised me that there are white wolves and black wolves but no gray wolves in these areas," Musiani said. "This work may provide an explanation: Wolf populations are quickly adapting to conditions with less snow by taking advantage of the human-created shortcut of black colouration." With tundra habitat expected to decline in coming years due to northern expansion of boreal forests related to global warming, the researchers note that black colouring may also help gray wolves adapt to their changing environment. "It is somewhat ironic that a trait that was created by humans may now prove to be beneficial for wolves as they deal with human-caused changes to their habitat," Musiani said.