"No one has ever suggested that before," Slater said.
The maned wolf, which lives on the grassy plains of Brazil and parts of Argentina, has long, thin legs and is often called the "fox on stilts." The bush dog, which lives in South American rain forests, is tiny, "like a toaster with legs on it," Wayne said. The bush dog hunts large rodents and animals that are much larger than itself, Slater said.
"Our findings firmly align the Falkland Islands wolf with the maned wolf, even though the divergence was fairly ancient, more than 6 million years," Wayne said. "They both probably evolved more than 6 million years ago in North America."
The research was federally funded by the National Science Foundation.
Wayne and Slater collected and analyzed DNA from five Falkland Islands wolves from the British Museum and museums in Philadelphia, Liverpool and New Zealand.
"We sequenced some regions of the mitochondrial genome," Wayne said. The mitochondria are the tiny powerhouses of the cell, whose generators burn food and produce most of a cell's energy. "We also analyzed gene sequences of the nucleus of the cell."
They sequenced sites in the genome of the cell nucleus that are found only in certain groups of related canids, such as South American foxes, the maned wolf and the bush dog; these species have a unique nucleotide DNA sequence.
Previously, some scientists thought the Falkland Islands wolf may have been a domesticated animal from the South American mainland that was brought over by native South Americans and was marooned on the islands.
"The problem is, as far as we know, there were never any permanent settlements on the Falkland Islands before European explorers arrived," Wayne said. "There has been no evidence to my mind of any kind of prehistoric occupation of the Falkland Islands; they are too remote, cold and not very hospitable."
Co-authors on the paper include Olaf Thalmann, a UCLA postdoctoral scholar in Wayne's laboratory; Jennifer Leonard, who earned her Ph.D. from UCLA and is now on the faculty of Sweden's Uppsala University; Rena Schweizer, a UCLA graduate student in Wayne's laboratory; Klaus-Peter Koepfli, a UCLA postdoctoral scholar in Wayne's laboratory; John Pollinger, Wayne's laboratory manager; Nicolas J. Rawlence; Jeremy J. Austin; and Alan Cooper.
In previous research, Wayne and colleagues used molecular genetic techniques to determine that dogs have ancient origins and that the first Americans to arrive in the New World more than 12,000 years ago brought domesticated dogs with them. They have also found that dogs have been living in close association with humans much longer than any other domestic animal, have confirmed that dogs evolved from wolves and have confirmed that today's domestic horse resulted from the interbreeding of many lines of wild horses in multiple locations and was not confined to a small area or a single culture. They also showed that nearly half of North American wolves have black coats as the result of historical matings between black dogs and wild gray wolves.
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