A Genetic Approach to the Study of Population Structure in White-tailed Deer PDF Download

Author: Joel David Anderson
Publisher:
ISBN:
Category :
Languages : en
Pages : 134

View

Book Description

Author: William Leroy Miller
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
Wildlife diseases are important stressors of natural populations and commonly impact species of management and conservation interest. Because of this, mitigating the negative effects of these diseases is a common goal of many management strategies. One of the key goals in areas of recent disease emergence is to minimize the geographic diffusion of diseases across landscapes so that nave populations remain minimally impacted. Prospective tools for predicting disease flow are particularly helpful in the initial stages of the epizootic cycle. Evaluating patterns of population structure, susceptibility, and connectivity can provide important insights into the potential spread of diseases across landscapes. Landscape genetic analyses, in particular, have proven particularly useful in elucidating these population characteristics. Chronic wasting disease, a fatal neurodegenerative disease of members of the family Cervidae, is a disease of particular concern due to the ecological and economic importance of infected species. Chronic wasting disease is caused by an infectious prion protein that can be passed by contact among individuals and/or through the use of shared environments. Contact among nave and infected individuals is thought to play an important role in the geographic diffusion of this disease, and management plans commonly focus on minimizing contact among these groups. Population structure and patterns of gene flow impact the distribution and occurrence of chronic wasting disease on landscape where it occurs. Thus, assessing these factors may help to identify effective management units and to predict transmission patterns within and among populations. Additionally, individual and population susceptibility to this disease is modulated by genetic variability in the prion protein (PRNP) gene, so evaluating transmission dynamics in tandem with spatial PRNP variability provides a means of assessing the innate vulnerability of populations to disease occurrence and establishment.In this study, I evaluated the genetic structure of white-tailed deer (Odocoileus virginianus) in the Mid-Atlantic region of the United States of America in order to evaluate factors that may influence the epizootiology of chronic wasting disease. I used a panel of 11 microsatellite markers to assess spatial genetic structure and gene flow. These markers were chosen from a large suite of available loci (106 candidate markers) identified from 58 previous or ongoing studies of white-tailed deer genetics. These markers were chosen because they were characterized by low genotyping error rates and were inferred to be broadly applicable across the range of white-tailed deer in North America given the geographic distribution of previous studies. I genotyped a total of 2222 individuals to assess spatial genetic structure of white-tailed deer in the Mid-Atlantic region. White-tailed deer conformed to a pattern of isolation-by-distance at both fine and broad spatial scales. Despite this, 11 distinct subpopulation clusters were identified throughout the region. The edges of these subpopulations were associated with high-volume traffic roads and areas of greater elevational relief. Despite significant structure, subpopulations maintained high rates of connectivity. There was evidence of hierarchical genetic structure with the bounds of larger population units generally corresponding to physiographic provinces. Subpopulation units defined this way are more likely to be an effective disease management unit relative to those commonly defined by anthropocentric boundaries. Population structure is only one factor influencing the geographic distribution of diseases. Cervids are farmed in this region, and several captive cervid facilities have experienced recent outbreaks of chronic wasting disease. Egression from infected facilities represents another potential pathway for transmission. I used a Bayesian assignment algorithm to test for captive egression and dispersal events among free-ranging populations, both of which may contribute to epizootic patterns. I found a low (2.0%) but significant proportion of free-ranging deer that assigned to captive origin. Two deer that were infected with chronic wasting disease had a high probability of sourcing from captive populations. The proportion of individuals that assigned to a migratory origin was as high as 13.8% among the four subsampling units, and the proportion of individuals with admixed ancestry was as high as 46.7%. This suggests dispersal is common and ongoing and is commensurate with the high migration rates reported previously. One deer infected with chronic wasting disease assigned to a migratory origin. These results may indicate that both captive egression and natural dispersal have the potential to contribute to the spread of this disease into previously uninfected regions.Individual susceptibility to chronic wasting disease is thought to be linked to variation at two single nucleotide polymorphisms in the PRNP gene. Thus, population-scale variability at these loci may influence the risk of infection and establishment. The Mid-Atlantic populations of white-tailed deer generally had a higher proportion of susceptible individuals relative to populations with a longer history of chronic wasting disease. Variability at these loci varied spatially within the region and generally conformed to patterns of population structure. This suggests that some populations may be more innately susceptible than others to chronic wasting disease establishment. Understanding patterns of population structure and susceptibility provides insights into the potential occurrence of chronic wasting disease but does not necessarily explain transmission dynamics among populations. Transmission is expected to be facilitated by dispersal, but how deer move among populations is likely a consequence of the underlying landscape matrix. I evaluated the correlation between landscape features and patterns of gene flow using a resistance surface modeling approach to identify potential transmission corridors. Patterns of genetic differentiation were best explained by a resistance surface including percent forest cover, elevational relief, and traffic volume. While large streams were also included in the resistance surface, landscape resistance related to streams was negligible. Elevational relief and traffic volume were less resistant features than areas of low forest cover, highlighting the permeability of these features to deer movement. Gene flow was facilitated through forested corridors in heterogeneous landscapes and was more diffuse in homogeneous landscapes. A large number of chronic wasting disease cases occurred in areas of high connectivity, indicating that these areas may influence disease transmission among distinct groups of deer. In conclusion, patterns of white-tailed deer genetic structure are cryptic and associated with features that are permeable to movement. Nevertheless, these features may influence the distribution of chronic wasting disease and the possibility for transmission among populations. Furthermore, spatial variability at loci associated with disease susceptibility suggests that some populations may be more innately at risk for disease establishment than others. Incorporating the inferred patterns of population structure, connectivity, and susceptibility into disease forecasting models represents a logical extension and may further elucidate the trends observed here. Other sources of infection, such as captive egression, may pose a risk independent of patterns predicted by natural population structure. Thus, joint consideration of anthropogenic and natural sources of infection may further aid in predicting future epizootic patterns.

Author: Michael Edward Nelson
Publisher:
ISBN:
Category : Deer populations
Languages : en
Pages : 172

View

Book Description

Author: Cherri Bell
Publisher:
ISBN:
Category : Molecular genetics
Languages : en
Pages : 240

View

Book Description

Author: Amy C. Kelly
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
In this study we used molecular techniques to examine deer movement and population structure in the context of chronic wasting disease transmission and spread. Chronic wasting disease is an infectious prion encephalopathy in cervids that is endemic to Colorado and Wyoming but has spread across the US within the last decade. Quantifying white-tailed deer movement and population structure in infected areas can facilitate predictions of CWD spread via deer dispersal. We analyzed microsatellite genotypes of white-tailed deer populations in southern Wisconsin and Illinois to quantify population level movements, genetic admixture and gender-biased dispersal patterns using FST and contingency tests. We also examined movements of individuals using assignment tests and spatial autocorrelation, and quantified dispersal events using parentage assignment. Finally, we compared genetic characteristics such as allelic diversity, heterozygosity and fixation indices between CWD infected and uninfected individuals to determine if CWD affects movement of white-tailed deer. Genetic characteristics were not different between CWD infected and uninfected deer, suggesting that changes in movement behaviors associated with clinical illness were not detectable with our molecular data. We found that both male and female deer move extensively in northern Illinois and southern Wisconsin, and that this movement could facilitate CWD spread via dispersal. In contrast, a few locations demonstrated reduced deer movement and female philopatry. One of these locations is a hotspot for CWD in Illinois, and it appears that reduced movements in this area could be exacerbating CWD transmission via direct contact among deer. The observed spatial heterogeneity in deer movement and population structure has important management implications as it allowed us to identify locations at risk for future CWD infection and areas in need of management. Our study was intented to guide population management and conservation, so we wanted to ensure that biological inferences were based on accurate genetic information. Therefore we identified sources of genotyping errors, evaluated measures to correct for their presence and provided recommendations to prevent their negative impacts. We detected null alleles in five of 13 previously evaluated microsatellites, and redesigned primers for two of these loci. Analytical corrections for null alleles were unable to fully prevent bias associated with these genotyping errors, and consequently, measures of population differentiation and kinship were negatively impacted. Our results demonstrate the importance of error evaluation during all stages of population studies, and emphasize the need to standardize procedures for genetic marker evaluation. Since chronic wasting disease management often involves decreasing deer densities to reduce the likelihood of disease occurrence and spread, we wanted to examine the genetic consequences of management in white-tailed deer herds. Increased removal of individuals can alter genetic characteristics of the population, cause a loss of genetic diversity, a decrease in fitness, or enable increased immigration. We compared allele frequencies among cohorts of deer to determine if culling changed the genetic composition of managed populations. Additionally, allele frequency distributions, heterozygosity, and genetic characteristics such as allelic richness and fixation indices were evaluated in pre- and post-cull deer populations to examine the effects of culling on effective population size, genetic differentiation and genetic diversity of white-tailed deer. Cohorts demonstrated little change in allele frequencies from year to year. However, evaluations of pre- and post-cull populations revealed increases in allelic richness and deficiencies in heterozygosity in post-cull populations, suggesting that these populations have received immigrants following intervention. Moreover, female deer, which tend to be philopatric, had significant changes in allele frequencies after culling was initiated. This study suggests that while reducing deer densities through culling enriches the genetic composition of deer, it could also result in immigration of CWD infected deer, and these potential ecological consequences need to be considered during the implementation of disease management plans. In this investigation, we also used landscape genetics to examine the effect of landscape features on dispersal and population boundaries of white-tailed deer. An awareness of how the landscape affects animal movement and genetic exchange between populations contributes to our understanding of wildlife ecology. By quantifying genetic structure across the landscape we have identified populations with high and low admixture and discovered gender specific barriers to deer movement that may contribute to CWD spread via dispersal. We found that rivers, streams and interstates contributed to the genetic structuring of females in the study area, but males were insensitive to these features. The observed variations in landscape use between males and females implies that CWD could spread via male movement relatively independently of natural and manmade landscape features, while CWD spread by females would occur over shorter distances because movement is inhibited by these landscape features. Certain genotypes of the prion gene (Prnp) have been shown to prolong disease progression and survival of CWD infected deer. Therefore, examining Prnp genotypes in CWD infected and uninfected deer populations can reveal associations between genotype and phenotype to determine if selective pressures are affecting Prnp allele frequencies. If selection is occurring, we would expect Prnp genotypes that prolong survival to be higher in infected populations compared to uninfected populations. To test this hypothesis, we sequenced Prnp of 219 (99 CWD positive and 120 CWD negative) deer from the CWD outbreak region of northern Illinois and southern Wisconsin. We also sampled deer from two uninfected populations: one ~150 km away from the outbreak region, and another ~300 km from the outbreak region. Twelve nucleotide polymorphisms, eight silent and four coding, were found in Prnp of the sampled populations. Five polymorphic loci had significantly different distributions of alleles between infected and uninfected individuals. Nucleotide base changes 60C/T, 285A/C, 286G/A, and 555C/T were observed with higher than expected frequencies in CWD negative animals suggesting disease resistance, while 153C/T was observed more than expected in positive animals, suggesting susceptibility. The total number of polymorphisms per animal, silent or coding, was negatively correlated to disease status. Polymorphisms 243T/A, 286G/A and 555C/T were found at higher than expected frequencies in uninfected populations. The total number of polymorphisms, both silent and coding, also differed between infected and uninfected populations. At the temporal scale examined, selection does not appear to be favoring genotypes associated with CWD resistance as these genotypes tended to have higher frequencies in uninfected populations. 0́3

Author: William F. Porter
Publisher:
ISBN:
Category : Biotic communities
Languages : en
Pages : 72

View

Book Description

Author: D.R. McCullough
Publisher: Springer Science & Business Media
ISBN: 9401128685
Category : Mathematics
Languages : en
Pages : 1156

View

Book Description
In 1984, a conference called Wildlife 2000: Modeling habitat relationships of terrestrial vertebrates, was held at Stanford Sierra Camp at Fallen Leaf Lake in the Sierra Nevada Mountains of California. The conference was well-received, and the published volume (Verner, J. , M. L. Morrison, and C. J. Ralph, editors. 1986. Wildlife 2000: modeling habitat relationships of terrestrial vertebrates, University of Wisconsin Press, Madison, Wisconsin, USA) proved to be a landmark publication that received a book award by The Wildlife Society. Wildlife 2001: populations was a followup conference with emphasis on the other major biological field of wildlife conservation and management, populations. It was held on July 29-31, 1991, at the Oakland Airport Hilton Hotel in Oakland, California, in accordance with our intent that this conference have a much stronger international representation than did Wildlife 2000. The goal of the conference was to bring together an international group of specialists to address the state of the art in wildlife population dynamics, and set the agenda for future research and management on the threshold of the 21st century. The mix of specialists included workers in theoretical, as well as practical, aspects of wildlife conservation and management. Three general sessions covered methods, modelling, and conservation of threatened species.

Author: David G. Hewitt
Publisher: CRC Press
ISBN: 1482295989
Category : Nature
Languages : en
Pages : 668

View

Book Description
Winner of the Wildlife Society Outstanding Edited Book Award for 2013! Winner of the Texas Chapter of The Wildlife Society Outstanding Book Award for 2011! Winner of a CHOICE Outstanding Academic Title Award for 2011! Biology and Management of White-tailed Deer organizes and presents information on the most studied large mammal species in the world. The book covers the evolutionary history of the species, its anatomy, physiology, and nutrition, population dynamics, and ecology across its vast range (from central Canada through northern South America). The book then discusses the history of management of white-tailed deer, beginning with early Native Americans and progressing through management by Europeans and examining population lows in the early 1900s, restocking efforts through the mid 1900s, and recent, overabundant populations that are becoming difficult to manage in many areas. Features: Co-published with the Quality Deer Management Association Compiles valuable information for white-tailed deer enthusiasts, managers, and biologists Written by an authoritative author team from diverse backgrounds Integrates white-tailed deer biology and management into a single volume Provides a thorough treatment of white-tailed deer antler biology Includes downloadable resources with color images The backbone of many state wildlife management agencies' policies and a featured hunting species through much of their range, white-tailed deer are an important species ecologically, socially, and scientifically in most areas of North America. Highly adaptable and now living in close proximity to humans in many areas, white-tailed deer are both the face of nature and the source of conflict with motorists, home-owners, and agricultural producers. Capturing the diverse aspects of white-tailed deer research, Biology and Management of White-tailed Deer is a reflection of the resources invested in the study of the species’ effects on ecosystems, predator-prey dynamics, population regulation, foraging behavior, and browser physiology.

Author: Jim Heffelfinger
Publisher: Texas A&M University Press
ISBN: 1603445331
Category : Nature
Languages : en
Pages : 311

View

Book Description
Author Jim Heffelfinger presents a wide array of data in a reader-friendly, well-organized way. With a clear mission to make his information not only helpful, but entertaining and attractive as well, each chapter focuses on a specific aspect of understanding deer. The clear, detailed table of contents will help readers flip right to the section they want to investigate. Not just hunters, but anyone who is interested in the deer of West Texas, Arizona, New Mexico, southern California, Nevada, Utah, Colorado, northern Mexico, or tribal lands will find this book to be an indispensable resource for understanding these familiar and fascinating animals. “Very few books on the subject of deer in any particular region lend themselves to being complete. Jim Heffelfinger’s book breaks the mold. It is by far the most comprehensive book on mule deer and white-tailed deer in the southwestern part of the United States, including Plains portions of Texas, Colorado, and New Mexico, I’ve ever read. Everything you ever wanted to know about these two deer species can be found in its pages . . . All of this under one cover and written in a style easy enough for the layperson to understand, but scientific enough for the professional biologist . . . Deer of the Southwest is a pleasure to read and should be part of every deer enthusiast’s library.”—Great Plains Research “An important reference for anyone interested in deer in the Southwest—managers and enthusiasts alike. Both enlightening and instructive, Deer of the Southwest is the ultimate source for understanding the history, management, and issues facing this resource. Jim Heffelfinger has solidified his reputation as the premier authority on deer in this region.”—Barry Hale, deer program manager, New Mexico Department of Game and Fish

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13

View

Book Description
Abstract: Social behavior of white-tailed deer (Odocoileus virginianus) can have important management implications. The formation of matrilineal social groups among female deer has been documented and management strategies have been proposed based on this well-developed social structure. Using radiocollared (n = 17) and hunter or vehicle-killed (n = 21) does, we examined spatial and genetic structure in white-tailed deer on a 7,000-ha portion of the Savannah River Site in the upper Coastal Plain of South Carolina, USA. We used 14 microsatellite DNA loci to calculate pairwise relatedness among individual deer and to assign doe pairs to putative relationship categories. Linear distance and genetic relatedness were weakly correlated (r = -0.08, P = 0.058). Relationship categories differed in mean spatial distance, but only 60% of first-degree-related doe pairs (full sibling or mother-offspring pairs) and 38% of second-degree-related doe pairs (half sibling, grandmother-granddaughter pairs) were members of the same social group based on spatial association. Heavy hunting pressure in this population has created a young age structure among does, where the average age is 2.5 years, and