6 research outputs found

    Estimation of effective population size (N[subscript e]) in an island population of feral horses (Equus caballus L.)

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    1 online resource (29 p.) : ill.Includes abstract.Includes bibliographical references (p. 26-29).A concern of conservation biology is the viability of small, isolated populations because these are expected to lose genetic diversity at a greater rate than large populations due to genetic drift. Factors such as non-random mating systems and population fluctuations are known to reduce genetic diversity in natural populations. The Sable Island Horse (Equus caballus L.) population exhibits these characteristics; as such it is an interesting population in which to explore change in genetic diversity over time. Effective population size (N[subscript e]) is the size of a Wright-Fisher ideal population exhibiting the same level of genetic drift as the study population. Comparison of N[subscript e] with census population size can be informative about the rate at which genetic diversity is changing in the study population, and about what factors are likely influencing patterns of genetic diversity. This study aimed to use the Sable Island Horse population as a case study of how traits known to reduce genetic diversity affect estimates of N[subscript e]. Heterozygosity (Ā±SE) of the population based on samples collected in 1987-88 was 0.560 (Ā±0.020). By 2011 heterozygosity had declined to 0.536 (Ā±0.018). The maximum range of N[subscript e] estimates was 20 to 244 individuals with 2011 estimates averaging 60.9 individuals. This is well below the census size of 150 to 400, which is consistent with expectations given the size, lack of migration, non-random mating system, and population fluctuations of the horse population. It seems that the population has not yet reached mutation-drift equilibrium. Areas for future investigation include developing a pedigree of the horses and deeper investigation of the mating system, particularly in regards to mate choice and relatedness in harem bands

    Data from: Small N e of the isolated and unmanaged horse population on Sable Island

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    For small, isolated populations 2 common conservation concerns relate to genetic threats: inbreeding and negative consequences associated with loss of genetic diversity due to drift. Mitigating these threats often involves conservation actions that can be controversial, such as translocations or captive breeding programs. Although such actions have been successful in some situations, in others they have had undesirable outcomes. Here, we estimated the effective population size (N e) of the Sable Island horses to assess the risk to this population of these genetic threats. We found surprising consistency of N e estimates across the 5 different methods used, with a mean of 48 effective individuals. This estimate falls below the 50 criterion of the ā€œ50/500 rule,ā€ below which inbreeding depression is a concern for population viability. However, simulations and knowledge of population history indicate that this population is still in its early stages of approaching equilibrium between mutation, drift, and genetic diversity; and no negative consequences have been identified that could be associated with inbreeding depression. Therefore, we do not recommend taking management action (such as translocations) at this stage. Rather, we propose continued monitoring of genetic diversity and fitness over time so that trends and any substantial changes can be detected. This represents one of the few unmanaged horse populations in the world, and therefore these data will not only alert us to serious concerns regarding their conservation status, but will also provide a wealth of information about how natural processes drive patterns of reproduction, mortality, and population growth over time

    Data from: Small N e of the isolated and unmanaged horse population on Sable Island

    No full text
    For small, isolated populations 2 common conservation concerns relate to genetic threats: inbreeding and negative consequences associated with loss of genetic diversity due to drift. Mitigating these threats often involves conservation actions that can be controversial, such as translocations or captive breeding programs. Although such actions have been successful in some situations, in others they have had undesirable outcomes. Here, we estimated the effective population size (N e) of the Sable Island horses to assess the risk to this population of these genetic threats. We found surprising consistency of N e estimates across the 5 different methods used, with a mean of 48 effective individuals. This estimate falls below the 50 criterion of the ā€œ50/500 rule,ā€ below which inbreeding depression is a concern for population viability. However, simulations and knowledge of population history indicate that this population is still in its early stages of approaching equilibrium between mutation, drift, and genetic diversity; and no negative consequences have been identified that could be associated with inbreeding depression. Therefore, we do not recommend taking management action (such as translocations) at this stage. Rather, we propose continued monitoring of genetic diversity and fitness over time so that trends and any substantial changes can be detected. This represents one of the few unmanaged horse populations in the world, and therefore these data will not only alert us to serious concerns regarding their conservation status, but will also provide a wealth of information about how natural processes drive patterns of reproduction, mortality, and population growth over time

    Horse Genotypes

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    Genotypes of Sable Island horses at 10 microsatellite loci. Samples are from two time periods: 1987/1988 and 2011. File includes sample name, time period, and genotypes for all analyzed samples

    S100A10, a novel biomarker in pancreatic ductal adenocarcinoma

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    Pancreatic cancer is arguably the deadliest cancer type. The efficacy of current therapies is often hindered by the inability to predict patient outcome. As such, the development of tools for early detection and risk prediction is key for improving outcome and quality of life. Here, we introduce the plasminogen receptor S100A10 as a novel predictive biomarker and a driver of pancreatic tumor growth and invasion. We demonstrated that S100A10 mRNA and protein are overexpressed in human pancreatic tumors compared to normal ducts and nonductal stroma. S100A10 mRNA and methylation status were predictive of overall survival and recurrenceā€free survival across multiple patient cohorts. S100A10 expression was driven by promoter methylation and the oncogene KRAS. S100A10 knockdown reduced surface plasminogen activation, invasiveness, and inĀ vivo growth of pancreatic cancer cell lines. These findings delineate the clinical and functional contribution of S100A10 as a biomarker in pancreatic cancer
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