Mexican wolf

Abstract: The gray wolf is a large, highly mobile predator whose original geographic range included most of the Northern Hemisphere. High rates of genetic exchange probably characterized even distantly-separated populations in the past, but recent population declines and habitat fragmentation have isolated previously contiguous populations, especially in the Old World. We examine mitochondrial DNA (mtDNA) variability among twenty-six populations of wolves from throughout their geographic range. We find eighteen mtDNA genotypes in gray wolves, seven of these are derived from hybridization with coyotes, four are confined to the New World, six are confined to the Old World and one is shared by both areas. Genetic differentiation among wolf populations is significant but small in magnitude. In the Old World, most localities have a single unique genotype, whereas in the New World several genotypes occur at most localities and three of the five genotypes are nearly ubiquitous. The pattern of genetic differentiation in the gray wolf contrasts with that of another large, highly vagile canid, the coyote, in which genetic differentiation among populations is not significant even among widely separated localities. We suggest that the difference between these two species reflects the rapid, recent increase in coyote numbers and expansion of their geographic range, and the coincident decline in gray wolf populations. Apparent genetic differences among extant wolf populations may be a recent phenomenon reflecting population declines and habitat fragmentation rather than a long history of genetic isolation. El lobo gris es un predador grande y altamente mobil cuyo distribucion geografica original abarcaba la mayor parte del Hemisferio Norte. Es muy probable que en el pasado, altas tasas de intercambio genetico caracterizaran, incluso, poblaciones muy distantes. Sin embargo, recientes declinaciones poblacionales y fragmentacion del habitat han aislado poblaciones que antiguamente se escontraban, contiguas, especialmente en el Viejo Mundo. Examinamos la variabilidad en el ADN mitocondrial (mtDNA) de 26 poblaciones de lobos existentes a lo largo de toda su area de distribucion geografica. Encontramos 18 genotipos de mtDNA en lobos grises, de estos 7 son derivados de hibridacion con coyote, 4 estan confinados al Nuevo Mundo, 6 estan confinados al Viejo Mundo y uno esta presente en ambas areas. La diferenciacion genetica entre poblaciones de lobos es significativa pero de pequena magnitud. En el Viejo Mundo, la mayoria de las localidades tienen un unico genotipo especifico para cada loalidad, mientras que en el Nuevo Mundo, la mayoria de las localidades poseen varios genotipos, y tres de los cinco son aproximadamente cosmopolitas. El patron de diferenciacion genetica en el lobo gris contrasta conaquel de otro canido grande y altamente movil, el coyote, en el cual la diferenciacion genetica entre poblaciones no es significativa incluso en el casode localidades muy distantes. Sugerimos que la diferencia entre estas dos especies refleja el rapido y reciente incremento en el numero de coyotes, la expansion en su distribucion geografica y la declinacion en las poblaciones de lobos grises que ocurrio coincidentemente. La diferenciacion genetica entre las poblaciones de lobos existentes en la actualidad, puede ser un fenomeno reciente que refleja, antes que una largo historia de aislamiento genetico, la declinacion poblacional y fragmentacion del habitat.

Abstract: By the mid 20th century, the grey wolf ( Canis lupus ) was exterminated from most of the conterminous United States (cUS) and Mexico However, because wolves disperse over long distances, extant populations in Canada and Alaska might have retained a substantial proportion of the genetic diversity once found in the cUS We analysed mitochondrial DNA sequences of 34 pre-extermination wolves and found that they had more than twice the diversity of their modern conspecifics, implying a historic population size of several hundred thousand wolves in the western cUS and Mexico Further, two-thirds of the haplotypes found in the historic sample are unique Sequences from Mexican grey wolves ( C l baileyi ) and some historic grey wolves defined a unique southern clade supporting a much wider geographical mandate for the reintroduction of Mexican wolves than currently planned Our results highlight the genetic consequences of population extinction within Ice Age refugia and imply that restoration goals for grey wolves in the western cUS include far less area and target vastly lower population sizes than existed historically

Abstract: The Mexican gray wolf appears to be extinct in the wild and exists now only in captivity. There are three captive putative Mexican wolf lineages: Certified, Ghost Ranch, and Aragon lineages. From pedigree analysis, the Certified lineage has the lowest level of inbreeding and has retained the most founder alleles. In contrast, the Ghost Ranch has a high level of inbreeding and fewest founder alleles. From molecular genetics data, particularly from microsatellite loci, it appears that all of the lineages consist of Mexican wolves, and none of them appear to have ancestry from dogs or coyotes. Further, the molecular data are consistent with the- Certified lineage having three founders instead of the four previously assumed. From these findings, we recommend that the three lineages be combined to increase the number of founders and to postpone any inbreeding depression. The combination of pedigree analysis and molecular genetic data allowed us to resolve several long-standing concerns in Mexican wolves. Zoo Biol

Abstract: Mexican and red wolves were both faced with extinction in the wild until captive populations were established more than two decades ago. These captive populations have been successfully managed genetically to minimize mean kinship and retain genetic variation. Descendants of these animals were subsequently used to start reintroduced populations, which now number about 40-50 Mexican wolves in Arizona and New Mexico and about 100 red wolves in North Carolina. The original captive Mexican wolf population was descended from three founders. Merging this lineage with two other captive lineages, each with two founders, has been successfully carried out in the captive population and is in progress in the reintroduced population. This effort has resulted in increased fitness of cross-lineage wolves, or genetic rescue, in both the captive and reintroduced populations. A number of coyote-red wolf hybrid litters were observed in the late 1990s in the reintroduced red wolf population. Intensive identification and management efforts appear to have resulted in the elimination of this threat. However, population reintroductions of both Mexican and red wolves appear to have reached numbers well below the generally recommended number for recovery and there is no current effort to re-establish other populations.