Post by muskyhusky on Oct 18, 2008 18:57:33 GMT -6
by: Jody Haynes
As a molecular geneticist and evolutionary biologist, I find that Wayne's recent papers on the genetics of dogs and wolves show, quite clearly, that "[d]ogs are gray wolves, despite their diversity in size and proportion" (Wayne, 1993). Wayne's 1993 paper entitled "Molecular evolution of the dog family" (you can see it in the journal of Theoretical and Applied Genetics, v. 9, or *here ) www.grapevine.net/~wolf2dog/wayne2.htm provides clear-cut evidence--in the form of karyotypes (chromosome number and morphology) and nuclear and mitochondrial DNA markers--that there are four major phylogenetic divisions in the Family Canidae. The first of these divisions contains the wolf-like canids, including domestic dogs, gray wolves, coyotes, and jackals (Wayne, 1993).
Citing his earlier works, Wayne begins to elucidate the true genetic affinities shared by gray wolves and domestic dogs in this 1993 paper: The domestic dog is an extremely close relative of the gray wolf, differing from it by at most 0.2% of mtDNA sequence.... In comparison, the gray wolf differs from its closest wild relative, the coyote, by about 4% of mitochondrial DNA sequence" (Wayne, 1993). Thus, these data suggest that gray wolves are 20 times more closely related to dogs than to coyotes. Wayne and his colleagues later provide indisputable evidence that these different dog groups originated from different wolf populations in a paper entitled "Multiple and ancient origins of the domestic dog" (Science, v. 276, or *here www.grapevine.net/~wolf2dog/wayne1.htm); I should note here that this paper is published in one --of only two-- of the premier journals for ALL scientific disciplines on Earth.
Upon examining Fig. 1 in this latter paper, the untrained eye would likely see just many wolf mtDNA sequences differing from many dog mtDNA sequences. But Fig. 2--which shows a graphical representation of the results of extensive, cutting-edge phylogenetic analyses of the data shown, only in part, in Fig. 1-- shows the trained eye that, not only are wolves the direct and recent ancestor of dogs, but that the dogs in clades 2 and 4 are more closely related to wolves than they are to the dogs in clades 1 and 3. Thus, this figure also illuminates the polyphyletic nature of "dogs," in which "Dog" does not represent a genetically coherent group of organisms; to use the word to refer to only those many breeds of domestic canines selected by humans as companions is evolutionarily inaccurate.
Further, the group "dog" is paraphyletic because it excludes many genetically related organisms (i.e., gray wolves). To those of you who are not molecular geneticists or evolutionary biologists, this means that dogs are really not "dogs" at all, but simply a diverse group of modified wolves. It is my opinion that dogs should not even be afforded subspecies status under Canis lupus, since the wide variation in [the domestic dog's] adult morphology probably results from simple changes in developmental rate and timing" (Wayne, 1993), and because it is highly likely that backcrossing (matings between "dogs" and wolves) has provided the genetic raw material for artificial selection to produce the bewildering phenotypic diversity in the domestic dog (Wayne et al., 1997). I further believe that the word "dog" should still be used for "man's best friend," simply as a matter of convenience, even though it does not represent true genetic relatedness among its members.
www.idir.net/~wolf2dog/wdgenes.htm
As a molecular geneticist and evolutionary biologist, I find that Wayne's recent papers on the genetics of dogs and wolves show, quite clearly, that "[d]ogs are gray wolves, despite their diversity in size and proportion" (Wayne, 1993). Wayne's 1993 paper entitled "Molecular evolution of the dog family" (you can see it in the journal of Theoretical and Applied Genetics, v. 9, or *here ) www.grapevine.net/~wolf2dog/wayne2.htm provides clear-cut evidence--in the form of karyotypes (chromosome number and morphology) and nuclear and mitochondrial DNA markers--that there are four major phylogenetic divisions in the Family Canidae. The first of these divisions contains the wolf-like canids, including domestic dogs, gray wolves, coyotes, and jackals (Wayne, 1993).
Citing his earlier works, Wayne begins to elucidate the true genetic affinities shared by gray wolves and domestic dogs in this 1993 paper: The domestic dog is an extremely close relative of the gray wolf, differing from it by at most 0.2% of mtDNA sequence.... In comparison, the gray wolf differs from its closest wild relative, the coyote, by about 4% of mitochondrial DNA sequence" (Wayne, 1993). Thus, these data suggest that gray wolves are 20 times more closely related to dogs than to coyotes. Wayne and his colleagues later provide indisputable evidence that these different dog groups originated from different wolf populations in a paper entitled "Multiple and ancient origins of the domestic dog" (Science, v. 276, or *here www.grapevine.net/~wolf2dog/wayne1.htm); I should note here that this paper is published in one --of only two-- of the premier journals for ALL scientific disciplines on Earth.
Upon examining Fig. 1 in this latter paper, the untrained eye would likely see just many wolf mtDNA sequences differing from many dog mtDNA sequences. But Fig. 2--which shows a graphical representation of the results of extensive, cutting-edge phylogenetic analyses of the data shown, only in part, in Fig. 1-- shows the trained eye that, not only are wolves the direct and recent ancestor of dogs, but that the dogs in clades 2 and 4 are more closely related to wolves than they are to the dogs in clades 1 and 3. Thus, this figure also illuminates the polyphyletic nature of "dogs," in which "Dog" does not represent a genetically coherent group of organisms; to use the word to refer to only those many breeds of domestic canines selected by humans as companions is evolutionarily inaccurate.
Further, the group "dog" is paraphyletic because it excludes many genetically related organisms (i.e., gray wolves). To those of you who are not molecular geneticists or evolutionary biologists, this means that dogs are really not "dogs" at all, but simply a diverse group of modified wolves. It is my opinion that dogs should not even be afforded subspecies status under Canis lupus, since the wide variation in [the domestic dog's] adult morphology probably results from simple changes in developmental rate and timing" (Wayne, 1993), and because it is highly likely that backcrossing (matings between "dogs" and wolves) has provided the genetic raw material for artificial selection to produce the bewildering phenotypic diversity in the domestic dog (Wayne et al., 1997). I further believe that the word "dog" should still be used for "man's best friend," simply as a matter of convenience, even though it does not represent true genetic relatedness among its members.
www.idir.net/~wolf2dog/wdgenes.htm
