genetic monitoring

  • 文章类型: Journal Article
    Conservation translocations are an important conservation tool commonly employed to augment declining or reestablish extirpated populations. One goal of augmentation is to increase genetic diversity and reduce the risk of inbreeding depression (i.e., genetic rescue). However, introducing individuals from significantly diverged populations risks disrupting coadapted traits and reducing local fitness (i.e., outbreeding depression). Genetic data are increasingly more accessible for wildlife species and can provide unique insight regarding the presence and retention of introduced genetic variation from augmentation as an indicator of effectiveness and adaptive similarity as an indicator of source and recipient population suitability. We used 2 genetic data sets to evaluate augmentation of isolated populations of greater sage-grouse (Centrocercus urophasianus) in the northwestern region of the species range (Washington, USA) and to retrospectively evaluate adaptive divergence among source and recipient populations. We developed 2 statistical models for microsatellite data to evaluate augmentation outcomes. We used one model to predict genetic diversity after augmentation and compared these predictions with observations of genetic change. We used the second model to quantify the amount of observed reproduction attributed to transplants (proof of population integration). We also characterized genome-wide adaptive divergence among source and recipient populations. Observed genetic diversity (HO = 0.65) was higher in the recipient population than predicted had no augmentation occurred (HO = 0.58) but less than what was predicted by our model (HO = 0.75). The amount of shared genetic variation between the 2 geographically isolated resident populations increased, which is evidence of periodic gene flow previously assumed to be rare. Among candidate adaptive genes associated with elevated fixation index (FST) (143 genes) or local environmental variables (97 and 157 genes for each genotype-environment association method, respectively), we found clusters of genes with related functions that may influence the ability of transplants to use local resources and navigate unfamiliar environments and their reproductive potential, all possible reasons for low genetic retention from augmentation.
    Influencia potencial de la divergencia adaptativa a nivel genoma sobre el resultado de la reubicación para conservación en una población aislada de urogallo mayor Resumen Las reubicaciones para conservación son una herramienta importante que se usa con frecuencia para aumentar las poblaciones en declinación o reestablecer las poblaciones erradicadas. Una de las metas de este aumento es incrementar la diversidad genética y reducir el riesgo de depresión endogámica (es decir, rescate genético). Sin embargo, la introducción de individuos de una población con divergencia significativa puede perturbar los rasgos coadaptados y reducir la aptitud local (es decir, depresión exogámica). La información genética es cada vez más accesible para las especies silvestres y puede proporcionar conocimiento único con respecto a la presencia y retención de la variación genética introducida a partir del aumento como un indicador de eficiencia y las similitudes adaptativas como un indicador de la idoneidad de la población de origen y la receptora. Usamos dos conjuntos de datos genéticos para evaluar el aumento de las poblaciones aisladas del urogallo mayor (Centrocercus urophasianus) en la región noroeste de la distribución de la especie (Washington, EUA) y para evaluar de forma retrospectiva la divergencia adaptativa entre la población de origen y la receptora. Desarrollamos dos modelos estadísticos para los datos microsatelitales para así evaluar los resultados del aumento. Usamos un modelo para predecir la diversidad genética después del aumento y comparamos estas predicciones con observaciones del cambio genético. Usamos el segundo modelo para cuantificar el aumento de la reproducción observada atribuida a las reubicaciones (evidencia de la integración poblacional). También caracterizamos la divergencia adaptativa a nivel genoma entre la población de origen y la población receptora. La diversidad genética observada (HO = 0.65) fue mayor de lo que se predijo en la población receptora de no haber ocurrido el aumento (HO = 0.58) pero menor de lo que se predijo en nuestro modelo (HO = 0.75). El aumento de la variación genética compartida entre las dos poblaciones residentes geográficamente aisladas incrementó, lo cual es evidencia de un flujo génico periódico que antes se supuso casi no ocurría. Entre los genes adaptativos candidatos asociados a una FST elevada (143 genes) o a variables ambientales locales (97 y 157 genes para cada método de asociación entre el ambiente y el genotipo, respectivamente) encontramos grupos de genes con funciones relacionadas que pueden influir sobre la habilidad de cada reubicación para usar recursos locales y navegar ambientes desconocidos y su potencial reproductivo, todas posibles razones para la baja retención genética en el aumento.
    【摘要】保护性迁移是一项重要的保护工具, 通常用于帮助已衰退或灭绝后重建的种群进行增殖。增殖的目的之一是增加遗传多样性, 降低近交衰退的风险(即遗传拯救)。然而, 从明显分化的种群中引入个体有可能破坏共同适应性状, 降低局部适合度(即远交衰退)。野生动物的遗传数据已越来越容易获取, 这些数据可以提供独特的见解, 如了解通过增殖引入的遗传变异的存在和保留情况以指示有效性, 了解适应性相似性以指示源种群和迁入种群之间是否合适。我们利用两组遗传数据来评估艾草松鸡(Centrocercus urophasianus)分布区西北部(美国华盛顿州)的孤立种群的增殖情况, 并回顾性地评估了源种群和迁入种群之间的适应性分化。我们为微卫星数据开发了两个统计模型来评估增殖结果。我们使用一个模型预测增殖后的遗传多样性, 并将预测结果与观测到的遗传变化进行比较。我们使用第二个模型来量化观测到的迁入带来的繁殖量(证明发生种群融合)。我们还描述了源种群和迁入种群之间的全基因组适应性分化情况。观测到的迁入种群遗传多样性(HO = 0.65)高于未发生增殖的预测值(HO = 0.58), 但低于我们的模型预测值(HO = 0.75)。两个地理上隔离的种群之间共享遗传变异增加, 证明存在以往被认为十分少见的周期性基因流。在与FST升高(143个基因)或当地环境变量(每种基因型‐环境关联方法分别有97个和157个基因)相关的候选适应性基因中, 我们发现了可能会影响迁入个体利用当地资源和适应陌生环境的能力及其繁殖潜力的相关基因, 这些都可能是迁入个体基因保留率低的原因。【翻译:胡怡思;审校:聂永刚】.
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  • 文章类型: Journal Article
    哥伦比亚河流域太平洋鲑鱼的遗传监测为渔业管理人员提供了至关重要的信息,否则使用传统方法很难获得这些信息。诸如遗传种群鉴定(GSI)和基于亲子关系的标记(PBT)之类的监测程序涉及每年对成千上万的个体进行基因分型。虽然罕见,这些大样本集合不可避免地包括错误识别的物种,通过测序(GT-seq)面板在千种物种特异性基因分型中表现出低的基因分型成功率。对于参与大规模基因分型工作的实验室,诊断非目标物种并将其重新分配给适当的监测程序可能是昂贵且耗时的。为了解决这个问题,我们鉴定出19对引物,这些引物在salmonids中表现出一致的跨物种扩增,并且包含51个物种信息变异.这些遗传标记可靠地区分了11种鲑鱼和两个CutthrowatTrout亚种,并已包含在奇努克鲑鱼的特定物种GT-seq面板中,Coho三文鱼,Sockeye三文鱼,和彩虹鳟鱼通常用于太平洋鲑鱼遗传监测。大多数物种信息扩增子(16)是新从四个现有的GT-seq面板中鉴定出来的,因此,当使用靶向测序方法时,证明了一种低成本的物种鉴定方法。开发了一种物种调用脚本,该脚本是为常规GT-seq基因分型管道量身定制的,可以自动识别非目标物种。在用经验和模拟数据进行广泛测试之后,我们证明了遗传标记和伴随的脚本准确地识别了物种,并且对缺失的基因型数据和低频率具有鲁棒性,物种间共有的多态性。最后,我们使用这些工具来识别偶然捕获在哥伦比亚河奇努克鲑鱼运动渔业中的Coho鲑鱼,并使用PBT确定其孵化场。这些分子和计算资源为哥伦比亚河流域的太平洋鲑鱼保护提供了宝贵的工具,并展示了一种经济有效的遗传监测程序物种鉴定方法。
    Genetic monitoring of Pacific salmon in the Columbia River basin provides crucial information to fisheries managers that is otherwise challenging to obtain using traditional methods. Monitoring programs such as genetic stock identification (GSI) and parentage-based tagging (PBT) involve genotyping tens of thousands of individuals annually. Although rare, these large sample collections inevitably include misidentified species, which exhibit low genotyping success on species-specific Genotyping-in-Thousands by sequencing (GT-seq) panels. For laboratories involved in large-scale genotyping efforts, diagnosing non-target species and reassigning them to the appropriate monitoring program can be costly and time-consuming. To address this problem, we identified 19 primer pairs that exhibit consistent cross-species amplification among salmonids and contain 51 species informative variants. These genetic markers reliably discriminate among 11 salmonid species and two subspecies of Cutthroat Trout and have been included in species-specific GT-seq panels for Chinook Salmon, Coho Salmon, Sockeye Salmon, and Rainbow Trout commonly used for Pacific salmon genetic monitoring. The majority of species-informative amplicons (16) were newly identified from the four existing GT-seq panels, thus demonstrating a low-cost approach to species identification when using targeted sequencing methods. A species-calling script was developed that is tailored for routine GT-seq genotyping pipelines and automates the identification of non-target species. Following extensive testing with empirical and simulated data, we demonstrated that the genetic markers and accompanying script accurately identified species and are robust to missing genotypic data and low-frequency, shared polymorphisms among species. Finally, we used these tools to identify Coho Salmon incidentally caught in the Columbia River Chinook Salmon sport fishery and used PBT to determine their hatchery of origin. These molecular and computing resources provide a valuable tool for Pacific salmon conservation in the Columbia River basin and demonstrate a cost-effective approach to species identification for genetic monitoring programs.
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  • 文章类型: Journal Article
    荷斯坦牛种群中遗传性异常的患病率越来越高,这是一个紧迫的问题,导致诸如胚胎死亡率和无生命后代的出生等问题。这项研究通过开发替代诊断方法来解决在荷斯坦牛中管理有害基因突变的紧迫性。该研究旨在设计有效的方法来诊断牛的生育力单倍型HH1,HH3,HH5,HCD和BY以及低生育力综合征。为了实现这一目标,采用了一系列分子遗传技术,包括四引物ARMS-PCR方法,PCR-RFLP分析和等位基因特异性PCR。这些方法有助于在荷斯坦奶牛和服务公牛中鉴定各种生育力单倍型和低生育力综合征的杂合携带者。该研究揭示了哈萨克斯坦共和国牛种群中这些遗传缺陷的患病率。发现HH1,HH3,HH5,HCD和BY生育能力单倍型的发生率为1.4%至16.6%,在4.5%的西门塔尔公牛中发现了低生育综合征。这项研究的实际意义在于它对荷斯坦牛种群的遗传监测和管理策略的贡献。通过引入负担得起的,快速准确的诊断方法,例如T-ARMS-PCR,这项研究为控制和减轻有害基因突变的传播提供了有价值的工具,最终改善该地区荷斯坦牛的整体遗传健康和生产力。这项研究解决了养牛业的关键需求,并强调了遗传监测的重要性,以确保荷斯坦牛种群的长期生存能力和可持续性。
    The increasing prevalence of hereditary anomalies in Holstein cattle populations presents a pressing issue, leading to concerns such as embryonic mortality and the birth of non-viable offspring. This study addresses the urgency of managing harmful genetic mutations in Holstein cattle by developing alternative diagnostic methods. The research aims to devise effective means to diagnose fertility haplotypes HH1, HH3, HH5, HCD and BY and subfertility syndrome in cattle. To achieve this goal, a range of molecular genetic techniques were employed, including Tetra-Primer ARMS-PCR methods, PCR-RFLP analysis and allele-specific PCR. These methods facilitated the identification of heterozygous carriers of various fertility haplotypes and subfertility syndrome in Holstein cows and servicing bulls. The study reveals the prevalence of these genetic defects within the Republic of Kazakhstan\'s cattle population. HH1, HH3, HH5, HCD and BY fertility haplotypes were found to have occurrence rates ranging from 1.4% to 16.6%, with subfertility syndrome detected in 4.5% of Simmental bulls. The practical significance of this research lies in its contribution to genetic monitoring and management strategies for Holstein cattle populations. By introducing affordable, rapid and accurate diagnostic methods, such as the T-ARMS-PCR, the study provides a valuable tool for controlling and mitigating the spread of harmful genetic mutations, ultimately improving the overall genetic health and productivity of Holstein cattle in the region. This research addresses a critical need in the cattle breeding industry and underscores the importance of genetic monitoring to ensure the long-term viability and sustainability of Holstein cattle populations.
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  • 文章类型: Journal Article
    男性因素,通常与精液质量差有关,在大约50%的不孕夫妇中被发现。CFTR基因(囊性纤维化跨膜传导调节因子)变异是无精子症相关男性不育的常见遗传原因之一。值得注意的是,致病性CFTR变异的频谱和频率因人群和地理区域而异.在这项工作中,我们试图评估俄罗斯不育男性和来自俄罗斯不同地区的健康个体中12种常见CFTR变异的等位基因频率(AF).由于对俄罗斯个人的基于人群的研究数量有限,我们根据俄罗斯囊性纤维化(CF)患者登记处的数据对人群AF进行了定性.除了CF患者登记,我们根据局部生物采集(来自圣彼得堡和尤格拉地区)CF患者的基因分型结果,估计了同一组变异的局部频率.基于注册和生物采集数据计算的常见CFTR变体的AF与直接测量的群体AF显示出良好的一致性。CFTR变体的估计区域特定频率使我们能够发现F508del(c.1521_1523del;p.Phe508del)和CFTRdele2,3(21kb)(c.54-5940_27310250del21kb;p.Ser18ArgfsX)变体的频率的统计显着区域差异。基于人群的研究数据证实了以前的观察结果,即F508del,CFTRdele2,3(21kb),和L138ins(c.413_415dup;p.Leu138dup)变体在不育患者中最丰富,在健康个体中,其频率显着降低,在对俄罗斯个体的生殖健康进行遗传监测时应予以考虑。
    A male factor, commonly associated with poor semen quality, is revealed in about 50% of infertile couples. CFTR gene (Cystic Fibrosis Transmembrane Conduction Regulator) variants are one of the common genetic causes of azoospermia-related male infertility. Notably, the spectrum and frequency of pathogenic CFTR variants vary between populations and geographical regions. In this work, we made an attempt to evaluate the allele frequency (AF) of 12 common CFTR variants in infertile Russian men and healthy individuals from different districts of Russia. Because of the limited number of population-based studies on Russian individuals, we characterized the population AFs based on data from the Registry of Russian cystic fibrosis (CF) patients. In addition to the CF patient registry, we estimated the local frequencies of the same set of variants based on the results of genotyping of CF patients in local biocollections (from St. Petersburg and Yugra regions). AFs of common CFTR variants calculated based on registry and biocollection data showed good concordance with directly measured population AFs. The estimated region-specific frequencies of CFTR variants allowed us to uncover statistically significant regional differences in the frequencies of the F508del (c.1521_1523del; p.Phe508del) and CFTRdele2,3(21kb) (c.54-5940_273+10250del21kb; p.Ser18ArgfsX) variants. The data from population-based studies confirmed previous observations that F508del, CFTRdele2,3(21kb), and L138ins (c.413_415dup; p.Leu138dup)variants are the most abundant among infertile patients, and their frequencies are significantly lower in healthy individuals and should be taken into account during genetic monitoring of the reproductive health of Russian individuals.
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  • 文章类型: Journal Article
    在2000年代初期,文献中开始记录了历史上被占领的地点的美国鼠兔(Ochotonaprinceps)种群的减少和灭绝。与全球气候变化相称,外围和低海拔地区的许多损失与环境空气温度和降水状况的变化有关。这里,我们报告了美国标志性鼠兔群体的可用遗传资源下降,位于加利福尼亚州东部的BodieHills物种分布的西南边缘,美国。由坚硬岩石开采造成的高度分散的栖息地组成,大约在19世纪末,该地点的矿石堆放场可能被附近的天然距骨露头的鼠兔所占领。从当代样本和存档的自然历史收藏中提取的遗传数据使我们能够在过去半个世纪(1948-1949,1988-1991,2013-2015)的三个不同采样点跟踪Bodiepikas的种群和斑块级遗传多样性。在整个时间段内观察到种群内等位基因多样性和预期杂合性的降低。在1988-1991年和2013-2015年期间,对现有斑块进行了更广泛的采样,表明人口结构增加,有效人口规模减少。此外,过去51年的人口普查记录以及1947年从Wassuk山脉附近的鼠兔种群中收集的存档博物馆样本(内华达州,美国)为该地区发生的隔离和遗传合并增加提供了进一步的支持。这项研究强调了博物馆样本和长期监测在我们对人口生存能力的理解中的重要性。
    Declines and extirpations of American pika (Ochotona princeps) populations at historically occupied sites started being documented in the literature during the early 2000s. Commensurate with global climate change, many of these losses at peripheral and lower elevation sites have been associated with changes in ambient air temperature and precipitation regimes. Here, we report on a decline in available genetic resources for an iconic American pika metapopulation, located at the southwestern edge of the species distribution in the Bodie Hills of eastern California, USA. Composed of highly fragmented habitat created by hard rock mining, the ore dumps at this site were likely colonized by pikas around the end of the 19th century from nearby natural talus outcrops. Genetic data extracted from both contemporary samples and archived natural history collections allowed us to track population and patch-level genetic diversity for Bodie pikas across three distinct sampling points during the last half- century (1948-1949, 1988-1991, 2013-2015). Reductions in within-population allelic diversity and expected heterozygosity were observed across the full time period. More extensive sampling of extant patches during the 1988-1991 and 2013-2015 periods revealed an increase in population structure and a reduction in effective population size. Furthermore, census records from the last 51 years as well as archived museum samples collected in 1947 from a nearby pika population in the Wassuk range (Nevada, USA) provide further support of the increasing isolation and genetic coalescence occurring in this region. This study highlights the importance of museum samples and long-term monitoring in contextualizing our understanding of population viability.
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  • 文章类型: Journal Article
    Human water use combined with a recent megadrought have reduced river and stream flow through the southwest United States and led to periodic drying of formerly perennial river segments. Reductions in snowmelt runoff and increased extent of drying collectively threaten short-lived, obligate aquatic species, including the endangered Rio Grande silvery minnow (Hybognathus amarus). This species is subject to boom-and-bust population dynamics, under which large fluctuations in abundance are expected to lower estimates of effective population size and erode genetic diversity over time. Rates of diversity loss are also affected by additions of hatchery-origin fish used to supplement the wild population. We used demographic and genetic data from wild and hatchery individuals to examine the relationship of genetic diversity and effective population size to abundance over the last two decades. Genetic diversity was low during the early 2000s, but diversity and demographic metrics stabilized after the hatchery program was initiated and environmental conditions improved. Yet, from 2017 onward, allelic diversity declined (Cohen\'s d = 1.34) and remained low despite hatchery stocking and brief wild population recovery. Across the time series, single-sample estimates of effective population size based on linkage disequilibrium (LD Ne ) were positively associated (r = 0.53) with wild abundance and total abundance, but as the proportion of hatchery-origin spawners increased, LD Ne declined (r = -0.55). Megadrought limited wild spawner abundance and precluded refreshment of hatchery brood stocks with wild fish; hence, we predict a riverine population increasingly dominated by hatchery-origin individuals and accelerated loss of genetic diversity despite supplementation. We recommend an adaptive and accelerated management plan that integrates river flow management and hatchery operations to slow the pace of genetic diversity loss exacerbated by megadrought.
    El uso humano del agua, combinado con una megasequía reciente, ha reducido el flujo de los ríos y arroyos en el suroeste de los Estados Unidos y ha provocado la seca periódica de segmentos de ríos que antes eran perennes. Las reducciones en la escorrentía del deshielo y el aumento de la sequía amenazan colectivamente a especies obligatoriamente acuáticas de vida corta, incluyendo la amenazada carpa chamizal (Hybognathus amarus). Esta especie está sujeta a una dinámica poblacional de explosión y colapso, bajo la cual se espera que grandes fluctuaciones en la abundancia reduzcan las estimaciones del tamaño efectivo de la población y erosionen la diversidad genética con el tiempo. Las tasas de pérdida de la diversidad también se ven afectadas por la adición de peces procedentes de criaderos usados para suplementar la población silvestre. Utilizamos datos demográficos y genéticos de individuos silvestres y de criaderos para examinar la relación entre la diversidad genética y el tamaño efectivo de la población con la abundancia durante las últimas dos décadas. La diversidad genética fue baja a principios de los 2000, pero las métricas de diversidad y demografía estabilizaron después de que se inició el programa de criadero y mejoraron las condiciones ambientales. Sin embargo, a partir de 2017, la diversidad alélica disminuyó (d de Cohen = 1,34) y se mantuvo baja a pesar de la suplementación con individuos de criaderos y la breve recuperación de la población silvestre. A lo largo del tiempo, las estimativas de muestras individuales del tamaño efectivo de la población basados en el desequilibrio de ligamiento (LD Ne) estaban asociadas positivamente (r = 0,53) con la abundancia silvestre y la abundancia total, pero a medida que la proporción de desovadores originados en criaderos aumentó, el LD Ne disminuyó (r = -0,55). La megasequía limitó la abundancia de desovadores silvestres e impidió el reabastecimiento de las poblaciones en cautiverio con peces silvestres; por lo tanto, predecimos una población ribereña cada vez más dominada por individuos procedentes de criaderos y una pérdida acelerada de diversidad genética a pesar de la suplementación. Recomendamos un plan de gestión adaptativo y acelerado que integre la gestión del caudal del río y las operaciones de criaderos para frenar el ritmo de pérdida de diversidad genética exacerbada por la megasequía.
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  • 文章类型: Journal Article
    Understanding the evolutionary consequences of anthropogenic change is imperative for estimating long-term species resilience. While contemporary genomic data can provide us with important insights into recent demographic histories, investigating past change using present genomic data alone has limitations. In comparison, temporal genomics studies, defined herein as those that incorporate time series genomic data, utilize museum collections and repeated field sampling to directly examine evolutionary change. As temporal genomics is applied to more systems, species and questions, best practices can be helpful guides to make the most efficient use of limited resources. Here, we conduct a systematic literature review to synthesize the effects of temporal genomics methodology on our ability to detect evolutionary changes. We focus on studies investigating recent change within the past 200 years, highlighting evolutionary processes that have occurred during the past two centuries of accelerated anthropogenic pressure. We first identify the most frequently studied taxa, systems, questions and drivers, before highlighting overlooked areas where further temporal genomic studies may be particularly enlightening. Then, we provide guidelines for future study and sample designs while identifying key considerations that may influence statistical and analytical power. Our aim is to provide recommendations to a broad array of researchers interested in using temporal genomics in their work.
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  • 文章类型: Journal Article
    在过去的几个世纪中,许多陆地哺乳动物物种经历了广泛的种群减少,主要是由于人为的压力。对于一些物种来说,包括欧亚水獭(Lutralutra),环境和法律保护最近导致人口增长和部分历史范围的重新定居。虽然预示着保护的成功,从遗传的角度来看,只有很少的这样的恢复,即遗传变异性和连通性是否已经恢复。我们在这里使用英国水獭的大规模和长期遗传监测数据,其人口在1950年代至1970年代之间经历了有据可查的人口减少,探索21年人口再扩张的动态。我们使用15个微卫星基因座在1994年至2014年之间的五个时间点对来自威尔士和英格兰的水獭进行了基因分型。我们使用这种长期时间和大规模空间采样的组合来评估与遗传恢复有关的3个假设,即(i)亚群之间的基因流会随着时间的推移而增加,(ii)先前孤立种群的遗传多样性会增加,并且(iii)遗传结构会随着时间的推移而减弱。尽管我们发现亚种群之间的区域间基因流动和混合水平增加,杂合性或等位基因丰富度没有显著的时间变化。因此,主要亚群之间的遗传结构仍然很强,并显示出明显的历史连续性。这些发现凸显了濒危物种种群恢复的一个未被重视的方面:遗传恢复通常可能落后于空间和人口恢复的过程。换句话说,种群物理连接的恢复不一定导致遗传连接。我们的发现强调了遗传数据作为保护监测不可或缺的一部分的必要性,以便能够评估人口的潜在脆弱性。
    Numerous terrestrial mammal species have experienced extensive population declines during past centuries, due largely to anthropogenic pressures. For some species, including the Eurasian otter (Lutra lutra), environmental and legal protection has more recently led to population growth and recolonization of parts of their historic ranges. While heralded as conservation success, only few such recoveries have been examined from a genetic perspective, i.e. whether genetic variability and connectivity have been restored. We here use large-scale and long-term genetic monitoring data from UK otters, whose population underwent a well-documented population decline between the 1950s and 1970s, to explore the dynamics of a population re-expansion over a 21-year period. We genotyped otters from across Wales and England at five time points between 1994 and 2014 using 15 microsatellite loci. We used this combination of long-term temporal and large-scale spatial sampling to evaluate 3 hypotheses relating to genetic recovery that (i) gene flow between subpopulations would increase over time, (ii) genetic diversity of previously isolated populations would increase and that (iii) genetic structuring would weaken over time. Although we found an increase in inter-regional gene flow and admixture levels among subpopulations, there was no significant temporal change in either heterozygosity or allelic richness. Genetic structuring among the main subpopulations hence remained strong and showed a clear historical continuity. These findings highlight an underappreciated aspect of population recovery of endangered species: that genetic recovery may often lag behind the processes of spatial and demographic recovery. In other words, the restoration of the physical connectivity of populations does not necessarily lead to genetic connectivity. Our findings emphasize the need for genetic data as an integral part of conservation monitoring, to enable the potential vulnerability of populations to be evaluated.
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  • 文章类型: Journal Article
    Genetic variation is a well-known indicator of population fitness yet is not typically included in monitoring programs for sensitive species. Additionally, most programs monitor populations at one scale, which can lead to potential mismatches with ecological processes critical to species\' conservation. Recently developed methods generating hierarchically nested population units (i.e., clusters of varying scales) for greater sage-grouse (Centrocercus urophasianus) have identified population trend declines across spatiotemporal scales to help managers target areas for conservation. The same clusters used as a proxy for spatial scale can alert managers to local units (i.e., neighborhood-scale) with low genetic diversity, further facilitating identification of management targets. We developed a genetic warning system utilizing previously developed hierarchical population units to identify management-relevant areas with low genetic diversity within the greater sage-grouse range. Within this warning system we characterized conservation concern thresholds based on values of genetic diversity and developed a statistical model for microsatellite data to robustly estimate these values for hierarchically nested populations. We found that 41 of 224 neighborhood-scale clusters had low genetic diversity, 23 of which were coupled with documented local population trend decline. We also found evidence of cross-scale low genetic diversity in the small and isolated Washington population, unlikely to be reversed through typical local management actions alone. The combination of low genetic diversity and a declining population suggests relatively high conservation concern. Our findings could further facilitate conservation action prioritization in combination with population trend assessments and (or) local information, and act as a base-line of genetic diversity for future comparison. Importantly, the approach we used is broadly applicable across taxa.
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  • 文章类型: Journal Article
    未经证实:很少有研究对鸡进行基因监测,也没有对鸭子进行过研究。为确保重点鸭品种的可持续管理,我们使用微卫星标记来监测棕色柴雅鸭的基因。
    未经评估:第二个,第四,本研究选择了第6至8代棕色柴鸭的饲喂效率和对照品系,以调查遗传变异,有效人口规模,群体结构和群体之间随时间的分化与11个微卫星标记来自棕色泽雅鸭。
    UNASSIGNED:结果表明,两个品系的遗传变异略有下降,种群内近交系数(FIS)增加,但在各行中没有观察到FIS的一致增加。第二和第八代的有效种群数量对于选定的品系为27.2,对于对照品系为23.9。等位基因丰富度(AR)的变化随时间呈下降趋势,并且所选择的线在每一代中都略低于控制线。所选品系中的私有等位基因(Np)数量高于对照品系。在选定的品系(FST=0.0510)和对照品系(FST=0.0606)中,在第二代和第八代之间观察到中等分化。总的来说,区分倾向于随着每一代的增加而增加,但是在两个品系中经过六代后,遗传变异和结构没有很大变化。
    UNASSIGNED:这项研究将作为家禽保护的参考,并有助于在其他鸭品种或品系中实施跨代遗传监测和育种计划,以促进可持续管理。
    OBJECTIVE: Few studies have genetically monitored chickens over time, and no research has been conducted on ducks. To ensure the sustainable management of key duck breeds, we used microsatellite markers to monitor Brown Tsaiya ducks over time genetically.
    METHODS: The second, fourth, sixth to eighth generations of the Brown Tsaiya duck selected for feeding efficiency and control lines were included in this study to investigate the genetic variations, effective population size, population structure and the differentiation between populations over time with 11 microsatellite markers derived from Brown Tsaiya duck.
    RESULTS: The results showed there were a slight decrease in the genetic variations and an increase in within-population inbreeding coefficient (FIS) in both lines, but no consistent increase in FIS was observed in each line. The effective population size in the second and eighth generations was 27.2 for the selected line and 23.9 for the control line. The change in allele richness showed a downward trend over time, and the selected line was slightly lower than the control line in each generation. The number of private alleles (Np) in the selected line were higher than in the control line. Moderate differentiation was observed between the second and eighth generations in the selected line (FST = 0.0510) and the control line (FST = 0.0606). Overall, differentiation tended to increase with each generation, but genetic variation and structure did not change considerably after six generations in the two lines.
    CONCLUSIONS: This study provides a reference for poultry conservation and helps to implement cross-generation genetic monitoring and breeding plans in other duck breeds or lines to promote sustainable management.
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