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Hybridization among western whiptail lizards (Cnemidophorus tigris) in southwestern New Mexico : population genetics, morphology, and ecology in three contact zones. Bulletin of the AMNH ; no. 246

Show simple item record Dessauer, Herbert C. en_US Cole, Charles J. en_US Townsend, Carol R. en_US 2005-10-06T15:25:04Z 2005-10-06T15:25:04Z 2000 en_US
dc.description 148 p. : ill. (some col.), maps ; 26 cm. en_US
dc.description Includes bibliographical references (p. 122-127). en_US
dc.description.abstract "Cnemidophorus tigris punctilinealis of the Sonoran Desert and C. t. marmoratus of the Chihuahuan Desert contact each other and interbreed in the Animas Valley of southwestern New Mexico. More than 600 specimens have been examined from the contact region, and data on biochemical genetics (mitochondrial DNA haplotypes, protein electrophoresis of nuclear gene products), chromosomes, external morphology (coloration, size, scalation), reproduction, and fitness have been compared for three hybrid zones. Habitats in the contact region were mapped and photographed, and they are discussed in the context of vegetational changes during Pleistocene to Recent times, which affected the geographic distribution of these animals. Data from mitochondrial DNA, allele frequencies at four protein loci (of 36 analyzed), and body coloration demonstrate that the areas of contact have steep, concordant, and coincident step-clines in which most gene exchange occurs in hybrid zones that are 3.2-7.8 km wide. Analyses of allele frequencies, genotype frequencies, and fixation indices (including Hardy-Weinberg equilibrium, linkage equilibrium, and cytonuclear equilibrium) indicate a population structure determined primarily by random mating and an absence of selection against hybrids. Estimates of gene flow indicate that the clines resulted from neutral secondary contact initiated with the newest reconnection of the Sonoran and Chihuahuan deserts within the present interglacial episode, from 1000 to 5000 years ago. This timeframe is consistent with paleoecological data from packrat middens. Analyses of karyotypes, morphology, reproduction, and physiology also fail to detect differences in fitness among lizards with various genotypes. Although it is possible that there are fitness differences that are too small to be detected by the sample sizes we employed, the data indicate that reproductive success, fitness, and the dynamics of populations within the hybrid zones presently are no different from those in nonhybrid populations. Earlier data, which suggested that one of the step-clines was moving, are not supported. The clines are located in fragile semiarid habitats that are subject to desertification. Consequently, we present considerable data and dated photographs of habitats, precise locations of sampling sites, and local allele frequencies, so that future investigators can monitor changes in position, width, or dynamics of these hybrid zones. In addition, the population genetics data are discussed in the context of the following: (1) absence of rare, apparently novel alleles forming in the hybrid zones; (2) genetic comparisons with additional subspecies of C. tigris (C. t. aethiops and C. t. septentrionalis); and (3) interspecific hybridization between C. tigris and other whiptail lizards of either bisexual or unisexual (parthenogenetic, clonal) species. Cnemidophorus tigris is one of the ancestors of some of the parthenogens, which are of hybrid origin, and our interest in their evolutionary history fuels our efforts to improve understanding of hybridization among whiptail lizards"--P. 4. en_US
dc.format.extent 7956937 bytes
dc.format.mimetype application/pdf
dc.language eng en_US
dc.language.iso en_US
dc.publisher [New York] : American Museum of Natural History en_US
dc.relation.ispartofseries Bulletin of the American Museum of Natural History ; no. 246 en_US
dc.subject.lcc QH1 .A4 no.246, 2000 en_US
dc.subject.lcsh Cnemidophorus tigris -- Genetics. en_US
dc.subject.lcsh Hybridization. en_US
dc.subject.lcsh Lizards -- New Mexico -- Genetics. en_US
dc.subject.lcsh Reptiles -- New Mexico -- Genetics. en_US
dc.title Hybridization among western whiptail lizards (Cnemidophorus tigris) in southwestern New Mexico : population genetics, morphology, and ecology in three contact zones. Bulletin of the AMNH ; no. 246 en_US
dc.title.alternative Hybridization in whiptail lizards en_US
dc.title.alternative Hybridization among whiptail lizards en_US
dc.type text en_US

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  • Bulletin of the American Museum of Natural History
    The Bulletin, published continuously since 1881, consists of longer monographic volumes in the field of natural sciences relating to zoology, paleontology, and geology. Current numbers are published at irregular intervals. The Bulletin was originally a place to publish short papers, while longer works appeared in the Memoirs. However, in the 1920s, the Memoirs ceased and the Bulletin series began publishing longer papers. A new series, the Novitates , published short papers describing new forms.

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