Publications by authors named "Bradley N White"

Range expansion is a widespread biological process, with well-described theoretical expectations associated with the colonization of novel ranges. However, comparatively few empirical studies address the genomic outcomes accompanying the genome-wide consequences associated with the range expansion process, particularly in recent or ongoing expansions. Here, we assess two recent and distinct eastward expansion fronts of a highly mobile carnivore, the coyote (), to investigate patterns of genomic diversity and identify variants that may have been under selection during range expansion.

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The processes leading to genetic isolation influence a population's local extinction risk, and should thus be identified before conservation actions are implemented. Natural or human-induced circumstances can result in historical or contemporary barriers to gene flow and/or demographic bottlenecks. Distinguishing between these hypotheses can be achieved by comparing genetic diversity and differentiation in isolated vs.

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Background: A clear association of amino acid variation in the prion protein gene (PRNP) with susceptibility and resistance to classical scrapie exists in sheep, but not in goats. In this study we examined DNA sequence variation in the PRNP of 149 animals from two scrapie-infected herds of Saanen dairy goats, and identified 6 non-synonymous variants in the coding region.

Results: In the larger herd, all of the 54 scrapie-affected goats tested had at least one allele with the arginine (R) codon at position 211, with 52 being homozygous for that variant.

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Local adaptation is necessary for population survival and depends on the interplay between responses to selective forces and demographic processes that introduce or retain adaptive and maladaptive attributes. Host-parasite systems are dynamic, varying in space and time, where both host and parasites must adapt to their ever-changing environment in order to survive. We investigated patterns of local adaptation in raccoon populations with varying temporal exposure to the raccoon rabies virus (RRV).

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North Atlantic right whales have one of the lowest levels of genetic variation at minisatellite loci, microsatellite loci, and mitochondrial control region haplotypes among mammals. Here, adaptive variation at the peptide binding region of class I and class II DRB-like genes of the major histocompatibility complex was assessed. Amplification of a duplicated region in 222 individuals revealed at least 11 class II alleles.

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Hybridization has played an important role in the evolutionary history of Canis species in eastern North America. Genetic evidence of coyote-dog hybridization based on mitochondrial DNA (mtDNA) is lacking compared to that based on autosomal markers. This discordance suggests dog introgression into coyotes has potentially been male biased, but this hypothesis has not been formally tested.

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There has been considerable discussion on the origin of the red wolf and eastern wolf and their evolution independent of the gray wolf. We analyzed mitochondrial DNA (mtDNA) and a Y-chromosome intron sequence in combination with Y-chromosome microsatellites from wolves and coyotes within the range of extensive wolf-coyote hybridization, that is, eastern North America. The detection of divergent Y-chromosome haplotypes in the historic range of the eastern wolf is concordant with earlier mtDNA findings, and the absence of these haplotypes in western coyotes supports the existence of the North American evolved eastern wolf (Canis lycaon).

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Despite ethical arguments against lethal control of wildlife populations, culling is routinely used for the management of predators, invasive or pest species, and infectious diseases. Here, we demonstrate that culling of wildlife can have unforeseen impacts that can be detrimental to future conservation efforts. Specifically, we analyzed genetic data from eastern wolves (Canis lycaon) sampled in Algonquin Provincial Park (APP), Ontario, Canada from 1964 to 2007.

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To gain insight into the incursion of the raccoon variant of rabies into the raccoon population in three Canadian provinces, a collection of 192 isolates of the raccoon rabies virus (RRV) strain was acquired from across its North American range and was genetically characterized. A 516-nucleotide segment of the non-coding region between the G and L protein open reading frames, corresponding to the most variable region of the rabies virus genome, was sequenced. This analysis identified 119 different sequences, and phylogenetic analysis of the dataset supports the documented history of RRV spread.

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The first report of the raccoon variant of rabies virus was in Ontario, Canada in 1999. As part of the control of this outbreak a Point Infection Control (PIC) strategy of trapping and euthanizing vector species was implemented. To evaluate whether this strategy was indeed removing diseased animals, rabies diagnosis was performed on these specimens.

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Interpretation of the genetic composition and taxonomic history of wolves in the western Great Lakes region (WGLR) of the United States has long been debated and has become more important to their conservation given the recent changes in their status under the Endangered Species Act. Currently, the two competing hypotheses on WGLR wolves are that they resulted from hybridization between (i) grey wolves (Canis lupus) and western coyotes (C. latrans) or (ii) between grey wolves and eastern wolves (C.

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Background: Phylogenetic studies of wild Canis species have relied heavily on the mitochondrial DNA control region (mtDNA CR) to infer species relationships and evolutionary lineages. Previous analyses of the CR provided evidence for a North American evolved eastern wolf (C. lycaon), that is more closely related to red wolves (C.

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Mitochondrial heteroplasmy has been identified in a variety of species and can result from either paternal leakage, whereby sperm mitochondria enter the ova during fertilization, or more commonly by the "survival" and proliferation of mutant variants within an organism. From an evolutionary perspective, this process represents the generation of new mitochondrial diversity within a species. Although this has been documented in some mammalian species, it has been reported from relatively few wild mammalian populations and in no wild nonhuman population has the transfer and segregation of mitochondrial heteroplasmy been tracked through multiple generations.

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A landscape genetic simulation modelling approach is used to understand factors affecting raccoon rabies disease spread in southern Ontario, Canada. Using the Ontario Rabies Model, we test the hypothesis that landscape configuration (shape of available habitat) affects dispersal, as indicated by genetic structuring. We simulated range expansions of raccoons from New York into vacant landscapes in Ontario, in two areas that differed by the presence or absence of a landscape constriction.

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The correlation of landscape features with genetic discontinuities reveals barriers to dispersal that can contribute to understanding present and future spread of wildlife diseases. This knowledge can then be used for targeting control efforts. The impact of natural barriers on raccoon dispersal was assessed through genetic analysis of samples from two regions, Niagara (N = 666) and St.

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The genetic status of wolves in the western Great Lakes region has received increased attention following the decision to remove them from protection under the US Endangered Species Act. A recent study of mitochondrial DNA has suggested that the recovered wolf population is not genetically representative of the historic population. We present microsatellite genotype data on three historic samples and compare them with extant populations, and interpret published genetic data to show that the pre-recovery population was admixed over a century ago by eastern wolf (Canis lycaon) and grey wolf (Canis lupus) hybridization.

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The entire genome of a mid-Atlantic raccoon strain rabies virus (RRV) isolated in Canada was sequenced; this is the second North American wildlife rabies virus isolate to be fully characterized. The overall organization and length of the genome was similar to that of other lyssaviruses. The nucleotide sequence identity of the raccoon strain ranged between 32.

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Landscape barriers influence movement patterns of animals, which in turn, affect spatio-temporal spread of infectious wildlife disease. We compare genetic data from computer simulations to those acquired from field samples to measure the effect of a landscape barrier on raccoon (Procyon lotor) movement, enabling risk assessment of raccoon rabies disease spread across the Niagara River from New York State into Ontario, an area currently uninfected by rabies. An individual-based spatially explicit model is used to simulate the expansion of a raccoon population to cross the Niagara River, for different permeabilities of the river to raccoon crossings.

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Optimizing the amount of primer to use in PCR amplification is one of the most important steps when developing protocols for genetic profiling, where subtle changes in primer concentration result in major impacts on the amount of desired product that is amplified. However; there are frequently discrepancies between the reported and actual quantity of primers delivered by suppliers, resulting in a need for re-optimization of conditions between primer orders and limiting the ability to standardize conditions between laboratories. To increase the consistency of genetic profiling protocols, we have developed a simple method to assess the quantity and quality of fluorescently labeled primers and therefore standardize reaction conditions through time and across laboratories.

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The Magadi tilapia (Alcolapia grahami, formerly Oreochromis alcalicus grahami) is a remarkable example of teleost life in an extreme environment. Typical conditions include water pH=10, titration alkalinity>300 mM, osmolality=525 mOsm, temperatures ranging from 23 degrees to 42 degrees C, and O(2) levels fluctuating diurnally between extreme hyperoxia and anoxia. A number of relatively small tilapia populations are present in various thermal spring lagoons around the margin of the lake separated by kilometers of solid trona crust (floating Na(2)CO(3)) underlain by anoxic water.

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The etiology of autism spectrum disorders (ASDs) is poorly understood, although it is clear that genetic factors play a major role. ASDs appear to be a heterogeneous group of disorders, making genetic analysis difficult in the absence of etiologically definable subgroups. The excess of males in the affected population has led to suggestions that an X-linked locus could play a role in the causation of autism or a related pervasive developmental disorder.

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We examined six historical specimens of the endangered North Atlantic right whale (Eubalaena glacialis) using DNA isolated from documented baleen plates from the late nineteenth and early twentieth centuries. Sequences from the mitochondrial DNA (mtDNA) control region from these samples were compared with those from a near-exhaustive survey (269 of approximately 320 individuals) of the remaining right whales in the western North Atlantic Ocean. Our results suggest that there has been only relatively modest change in maternal lineage diversity over the past century in the North Atlantic right whale population.

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We examined mitochondrial-DNA (mtDNA) sequence heterogeneity on four adjacent trapping grids in an island population of meadow voles (Microtus pennsylvanicus) at two different population densities. Four restriction endonucleases revealed 20 different mtDNA composite phenotypes in samples totaling 198 meadow voles. There were significant heterogeneities in the distribution of four common mtDNA composite phenotypes among the four trapping grids, suggesting that there is population subdivision on a fine scale.

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