conservation genetics

保护遗传学
  • 文章类型: Journal Article
    野生种群的长期遗传研究非常缺乏,但是对于连接生态和种群遗传学模型至关重要,以及理解生物多样性的动态。我们对36年的高空间分辨率采样的野生小麦种群进行了研究。在实验过程中,我们从定期采样的样片中对832个个体进行了基因分型。基因型在几十米的尺度上聚集到生态微生境中,在36代的研究中,这种聚类非常稳定。模拟表明,很难确定这种时空稳定性是否反映了极其有限的分散或精细尺度的局部适应生态参数。用一个普通的花园实验,我们表明,在不同微生境中发现的基因型在表型上有所不同。我们的结果为长期监测期内自然种群的种群遗传学提供了罕见的见解。
    Long-term genetic studies of wild populations are very scarce, but are essential for connecting ecological and population genetics models, and for understanding the dynamics of biodiversity. We present a study of a wild wheat population sampled over a 36-year period at high spatial resolution. We genotyped 832 individuals from regular sampling along transects during the course of the experiment. Genotypes were clustered into ecological microhabitats over scales of tens of metres, and this clustering was remarkably stable over the 36 generations of the study. Simulations show that it is difficult to determine whether this spatial and temporal stability reflects extremely limited dispersal or fine-scale local adaptation to ecological parameters. Using a common-garden experiment, we showed that the genotypes found in distinct microhabitats differ phenotypically. Our results provide a rare insight into the population genetics of a natural population over a long monitoring period.
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  • 文章类型: Journal Article
    尽管受威胁植物的非原位集合在它们包含最大遗传变异时最有用,收藏中遗传多样性的保护和维持通常鲜为人知。我们使用对Karomiagigas的非原位集合的群体基因组分析进行了案例研究,来自坦桑尼亚的极度濒危的热带树。在两个野生种群中只有约43个个体是已知的,并在两个地点从野生收集的种子中建立了包含34个个体的异地收集物。该研究旨在了解集合中代表了多少多样性,分析离境个体的亲子关系,并确定捕获和维持遗传多样性的有效策略。
    我们使用2b-RADseq方法对所有已知个体进行了基因分型,比较了野生种群和异地采集的遗传多样性,并对藏品进行了亲子关系分析。
    根据私有等位基因的数量,发现野生种群比离地种群具有更高的遗传多样性水平,多态位点的数量,观察到的和预期的杂合性,核苷酸多样性,和等位基因丰富度。此外,只有32.6%的野生个体在异地代表,许多个体被发现是单个野生个体自交的产物。
    群体基因组分析为K.gigas遗传多样性的保护提供了重要的见解,找出差距和低效率,但也强调了保护遗传多样性的策略。基因组分析提供了必要的信息,以确保馆藏有效地保护受威胁的热带树木的遗传多样性。
    UNASSIGNED: Although ex situ collections of threatened plants are most useful when they contain maximal genetic variation, the conservation and maintenance of genetic diversity in collections are often poorly known. We present a case study using population genomic analyses of an ex situ collection of Karomia gigas, a critically endangered tropical tree from Tanzania. Only ~43 individuals are known in two wild populations, and ex situ collections containing 34 individuals were established in two sites from wild-collected seed. The study aimed to understand how much diversity is represented in the collection, analyze the parentage of ex situ individuals, and identify efficient strategies to capture and maintain genetic diversity.
    UNASSIGNED: We genotyped all known individuals using a 2b-RADseq approach, compared genetic diversity in wild populations and ex situ collections, and conducted parentage analysis of the collections.
    UNASSIGNED: Wild populations were found to have greater levels of genetic diversity than ex situ populations as measured by number of private alleles, number of polymorphic sites, observed and expected heterozygosity, nucleotide diversity, and allelic richness. In addition, only 32.6% of wild individuals are represented ex situ and many individuals were found to be the product of selfing by a single wild individual.
    UNASSIGNED: Population genomic analyses provided important insights into the conservation of genetic diversity in K. gigas, identifying gaps and inefficiencies, but also highlighting strategies to conserve genetic diversity ex situ. Genomic analyses provide essential information to ensure that collections effectively conserve genetic diversity in threatened tropical trees.
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  • 文章类型: Journal Article
    背景:独居蜜蜂,如红色泥瓦匠蜜蜂(Osmiabicornis),提供重要的生态系统服务,包括授粉。面对全球传粉媒介数量的下降,这种单倍体膜翅目具有复杂的灭绝风险,由于遗传多样性有限。为了评估双目金丝雀种群的遗传多样性,我们开发了微卫星标记,并在两个种群中对其进行了表征。
    结果:微卫星序列是从最近发表的Osmiabicornis基因组中挖掘出来的,它是由来自英国的一只雄性蜜蜂提取的DNA组装而成的。鉴定出含有二核苷酸的序列,三核苷酸,和四核苷酸重复区。设计并测试了17个多态微卫星标记,其中16个被开发成四个多重PCR集,以促进廉价,快速有效的基因分型,并在来自德国(n=19)和英国(n=14)的无关女性中进行了表征。
    结论:微卫星标记信息丰富,组合排除概率为0.997(第一父母),这将使遗传结构和多样性的研究为这只蜜蜂的保护工作提供信息。
    BACKGROUND: Solitary bees, such as the red mason bee (Osmia bicornis), provide important ecosystem services including pollination. In the face of global declines of pollinator abundance, such haplodiploid Hymenopterans have a compounded extinction risk due to the potential for limited genetic diversity. In order to assess the genetic diversity of Osmia bicornis populations, we developed microsatellite markers and characterised them in two populations.
    RESULTS: Microsatellite sequences were mined from the recently published Osmia bicornis genome, which was assembled from DNA extracted from a single male bee originating from the United Kingdom. Sequences were identified that contained dinucleotide, trinucleotide, and tetranucleotide repeat regions. Seventeen polymorphic microsatellite markers were designed and tested, sixteen of which were developed into four multiplex PCR sets to facilitate cheap, fast and efficient genotyping and were characterised in unrelated females from Germany (n = 19) and England (n = 14).
    CONCLUSIONS: The microsatellite markers are highly informative, with a combined exclusion probability of 0.997 (first parent), which will enable studies of genetic structure and diversity to inform conservation efforts in this bee.
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  • 文章类型: Journal Article
    高通量测序技术的最新进展为获得表型性状变异的遗传基础的新见解提供了机会。到目前为止,我们对一般非模式生物,特别是天然脊椎动物种群的基因型-表型关联的理解的进展受到了野生动物种群通常可用的小样本量的阻碍,并因此缺乏统计能力,以及控制假阳性信号的能力有限。在这里,我们建议将全基因组关联研究(GWAS)和基于FST的方法与群体水平复制相结合,以部分克服这些限制。我们提供了一个案例研究,其中我们将这种方法与基因分型测序(GBS)单核苷酸多态性(SNP)数据结合使用,以鉴定与这种莱姆病的天然啮齿动物宿主中的疏螺旋体抗性或易感性相关的基因组区域。银行田鼠(Myodesglareolus)。使用这种组合方法,我们确定了位于Slc26a4,Tns3,Wscd1和Espnl基因外显子区域的四个共有SNP,这与种群内和跨种群的田鼠疏螺旋体感染状况显着相关。宿主对细菌感染的反应与大多数这些基因之间的功能联系先前已在其他啮齿动物系统中得到证实。使它们成为研究宿主对伯氏螺旋体出现的进化反应的新候选人。我们的方法适用于其他系统,可能有助于识别潜在的疾病抗性或易感性的遗传变异,以及其他生态相关特征,在野生动物种群中。
    Recent advances in high-throughput sequencing technologies provide opportunities to gain novel insights into the genetic basis of phenotypic trait variation. Yet to date, progress in our understanding of genotype-phenotype associations in nonmodel organisms in general and natural vertebrate populations in particular has been hampered by small sample sizes typically available for wildlife populations and a resulting lack of statistical power, as well as a limited ability to control for false-positive signals. Here we propose to combine a genome-wide association study (GWAS) and FST -based approach with population-level replication to partly overcome these limitations. We present a case study in which we used this approach in combination with genotyping-by-sequencing (GBS) single nucleotide polymorphism (SNP) data to identify genomic regions associated with Borrelia afzelii resistance or susceptibility in the natural rodent host of this Lyme disease-causing spirochete, the bank vole (Myodes glareolus). Using this combined approach we identified four consensus SNPs located in exonic regions of the genes Slc26a4, Tns3, Wscd1 and Espnl, which were significantly associated with the voles\' Borrelia infectious status within and across populations. Functional links between host responses to bacterial infections and most of these genes have previously been demonstrated in other rodent systems, making them promising new candidates for the study of evolutionary host responses to Borrelia emergence. Our approach is applicable to other systems and may facilitate the identification of genetic variants underlying disease resistance or susceptibility, as well as other ecologically relevant traits, in wildlife populations.
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  • 文章类型: Journal Article
    遗传多样性对于种群适应不断变化的环境至关重要。遗传多样性的测量通常基于选择性中性标记,比如微卫星。遗传多样性指导保护管理,然而,通过自适应标记更好地反映,包括主要组织相容性复合体(MHC)的基因。我们的目的是评估西澳大利亚州两个相反的宽吻海豚(Tursiopsaduncus)种群中的MHC和中性遗传多样性,其中一个显然可行的种群具有高生殖产量(鲨鱼湾),另一个具有较低的生殖产量,预计将下降(Bunbury)。我们通过对MHCII类DQB进行测序来评估两个种群的遗传变异,其包括功能上重要的肽结合区(PBR)。通过对23个微卫星基因座进行基因分型来评估中性遗传多样性。我们证实MHC是两个种群中的适应性标记。总的来说,鲨鱼湾种群比本伯里种群表现出更大的MHC多样性-例如,它显示出更大的MHC核苷酸多样性。相比之下,两个种群之间的微卫星多样性差异相对较低。我们的发现与以下假设一致:有活力的种群通常比有活力的种群表现出更大的遗传多样性。结果还表明,MHC变异比中性遗传变异与种群生存力更密切相关。虽然从我们的发现推断是有限的,因为我们只比较了两个种群,我们的结果增加了越来越多的研究,这些研究强调了MHC作为动物保护的潜在合适遗传标记的有用性。鲨鱼湾的人口,比Bunbury种群具有更大的适应性遗传多样性,因此,对它所居住的沿海生态系统的自然或人为变化可能更加稳健。
    Genetic diversity is essential for populations to adapt to changing environments. Measures of genetic diversity are often based on selectively neutral markers, such as microsatellites. Genetic diversity to guide conservation management, however, is better reflected by adaptive markers, including genes of the major histocompatibility complex (MHC). Our aim was to assess MHC and neutral genetic diversity in two contrasting bottlenose dolphin (Tursiops aduncus) populations in Western Australia-one apparently viable population with high reproductive output (Shark Bay) and one with lower reproductive output that was forecast to decline (Bunbury). We assessed genetic variation in the two populations by sequencing the MHC class II DQB, which encompasses the functionally important peptide binding regions (PBR). Neutral genetic diversity was assessed by genotyping twenty-three microsatellite loci. We confirmed that MHC is an adaptive marker in both populations. Overall, the Shark Bay population exhibited greater MHC diversity than the Bunbury population-for example, it displayed greater MHC nucleotide diversity. In contrast, the difference in microsatellite diversity between the two populations was comparatively low. Our findings are consistent with the hypothesis that viable populations typically display greater genetic diversity than less viable populations. The results also suggest that MHC variation is more closely associated with population viability than neutral genetic variation. Although the inferences from our findings are limited, because we only compared two populations, our results add to a growing number of studies that highlight the usefulness of MHC as a potentially suitable genetic marker for animal conservation. The Shark Bay population, which carries greater adaptive genetic diversity than the Bunbury population, is thus likely more robust to natural or human-induced changes to the coastal ecosystem it inhabits.
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  • 文章类型: Journal Article
    Molecular genetic estimates of population effective size (Ne ) lose accuracy and precision when insufficient numbers of samples or loci are used. Ideally, researchers would like to forecast the necessary power when planning their project. neogen (genetic Ne for Overlapping Generations) enables estimates of precision and accuracy in advance of empirical investigation and allows exploration of the power available in different user-specified age-structured sampling schemes. neogen provides a population simulation and genetic power analysis framework that simulates the demographics, genetic composition, and Ne , from species-specific life history, mortality, population size, and genetic priors. neogen guides the user to establish a tractable sampling regime and to determine the numbers of samples and microsatellite or SNP loci required for accurate and precise genetic Ne estimates when sampling a natural population. neogen is useful at multiple stages of a study\'s life cycle: when budgeting, as sampling and locus development progresses, and for corroboration when empirical Ne estimates are available. The underlying model is applicable to a wide variety of iteroparous species with overlapping generations (e.g., mammals, birds, reptiles, long-lived fishes). In this paper, we describe the neogen model, detail the workflow for the point-and-click software, and explain the graphical results. We demonstrate the use of neogen with empirical Australian east coast zebra shark (Stegostoma fasciatum) data. For researchers wishing to make accurate and precise genetic Ne estimates for overlapping generations species, neogen facilitates planning for sample and locus acquisition, and with existing empirical genetic Ne estimates neogen can corroborate population demographic and life history properties.
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  • 文章类型: Journal Article
    Domestication has been influenced by formal plant breeding since the onset of intensive agriculture and the Green Revolution. Despite providing food security for some regions, intensive agriculture has had substantial detrimental consequences for the environment and does not fulfill smallholder\'s needs under most developing countries conditions. Therefore, it is necessary to look for alternative plant production techniques, effective for each environmental, socio-cultural, and economic conditions. This is particularly relevant for countries that are megadiverse and major centers of plant domestication and diversification. In this white paper, a Mexico-centered initiative is proposed, with two main objectives: (1) to study, understand, conserve, and sustainably use the genetic diversity of domesticated plants and their wild relatives, as well as the ongoing evolutionary processes that generate and maintain it; and (2) to strengthen food and forestry production in a socially fair and environmentally friendly way. To fulfill these objectives, the initiative focuses on the source of variability available for domestication (genetic diversity and functional genomics), the context in which domestication acts (breeding and production) and one of its main challenges (environmental change). Research on these components can be framed to target and connect both the theoretical understanding of the evolutionary processes, the practical aspects of conservation, and food and forestry production. The target, main challenges, problems to be faced and key research questions are presented for each component, followed by a roadmap for the consolidation of this proposal as a national initiative.
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  • 文章类型: Journal Article
    这里,我们探索了巴西大西洋森林内Ocbil景观中位于花岗岩inselbergs上的Encholiumhordum种群之间的连通性的历史和同期模式,使用核和叶绿体微卫星标记。除了评估大肠杆菌种群的遗传结构,我们建立了四个时期的物种分布模型(当前情况,中全新世,最后一次冰川最大值[LGM],和最后间冰期),并使用最小成本路径分析来阐明生物地理模式。总的来说,在细胞核和质体DNA的种群之间,估计有很高的遗传差异(分别为ΦST(n)=0.463和ΦST(质体)=0.961,p<.001)。对于核基因组,种群之间几乎完全没有遗传混合和非常低的迁移率是显而易见的,在恐怖人群中观察到的移民和移民率估计非常低,这一点得到了证实。根据cpDNA的结果,在第四纪气候波动的周期中,糖块土地的假定扩散路线表明,在这些事件中,种群的连通性变化不大。遗传分析强调了种群的低遗传连通性和长期持久性,创始人效应和遗传漂移似乎是非常重要的过程,塑造了当前在两个基因组中观察到的多样性和遗传结构。每个种群的遗传奇异性清楚地表明,需要对所有种群进行原位保护。
    Here, we explore the historical and contemporaneous patterns of connectivity among Encholirium horridum populations located on granitic inselbergs in an Ocbil landscape within the Brazilian Atlantic Forest, using both nuclear and chloroplast microsatellite markers. Beyond to assess the E. horridum population genetic structure, we built species distribution models across four periods (current conditions, mid-Holocene, Last Glacial Maximum [LGM], and Last Interglacial) and inferred putative dispersal corridors using a least-cost path analysis to elucidate biogeographic patterns. Overall, high and significant genetic divergence was estimated among populations for both nuclear and plastid DNA (ΦST(n) = 0.463 and ΦST(plastid) = 0.961, respectively, p < .001). For nuclear genome, almost total absence of genetic admixture among populations and very low migration rates were evident, corroborating with the very low estimates of immigration and emigration rates observed among E. horridum populations. Based on the cpDNA results, putative dispersal routes in Sugar Loaf Land across cycles of climatic fluctuations in the Quaternary period revealed that the populations\' connectivity changed little during those events. Genetic analyses highlighted the low genetic connectivity and long-term persistence of populations, and the founder effect and genetic drift seemed to have been very important processes that shaped the current diversity and genetic structure observed in both genomes. The genetic singularity of each population clearly shows the need for in situ conservation of all of them.
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  • 文章类型: Review
    近亲繁殖的抑郁症(个体与相关父母的适应性降低)长期以来一直是生态学的主要焦点,进化,和保护生物学。尽管经过几十年的研究,我们对力量的了解仍然有限,潜在的遗传机制,以及野外近亲繁殖抑郁症的人口后果。无法精确测量个体近亲繁殖,阻碍了对自然种群近亲繁殖抑郁症的研究。幸运的是,高通量测序数据的快速增加的可用性意味着现在可以高精度地测量任何个体的近亲繁殖.这里,我们回顾了基因组数据如何促进我们对野外近亲繁殖抑郁症的理解。最近的结果表明,与传统的谱系分析相比,使用基因组数据可以更精确地测量个体近亲繁殖和近亲繁殖抑郁。此外,基因组数据的可用性使得有可能精确定位对野生种群近亲繁殖抑郁症有很大影响的基因座,尽管由于统计能力低,这在许多研究系统中仍然是一项具有挑战性的任务。现在,可靠地测量个体近亲繁殖不再是一个限制,未来研究的主要重点应该是更准确地量化近交抑郁对种群增长和生存能力的影响。
    Inbreeding depression (reduced fitness of individuals with related parents) has long been a major focus of ecology, evolution, and conservation biology. Despite decades of research, we still have a limited understanding of the strength, underlying genetic mechanisms, and demographic consequences of inbreeding depression in the wild. Studying inbreeding depression in natural populations has been hampered by the inability to precisely measure individual inbreeding. Fortunately, the rapidly increasing availability of high-throughput sequencing data means it is now feasible to measure the inbreeding of any individual with high precision. Here, we review how genomic data are advancing our understanding of inbreeding depression in the wild. Recent results show that individual inbreeding and inbreeding depression can be measured more precisely with genomic data than via traditional pedigree analysis. Additionally, the availability of genomic data has made it possible to pinpoint loci with large effects contributing to inbreeding depression in wild populations, although this will continue to be a challenging task in many study systems due to low statistical power. Now that reliably measuring individual inbreeding is no longer a limitation, a major focus of future studies should be to more accurately quantify effects of inbreeding depression on population growth and viability.
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  • 文章类型: Journal Article
    记录的风力涡轮机上蝙蝠的死亡人数引起了人们对风力发电发展增加对迁徙蝙蝠种群的未来影响的严重担忧。然而,对于大多数蝙蝠物种,我们不知道种群的规模和人口趋势,构造成离散亚群的程度,以及不同的亚群是否使用空间隔离的迁徙路线。这里,我们利用东部红蝙蝠(Lasiurusborealis)的遗传数据,北美受风力发电发展影响最大的物种之一,(1)评估整个景观的人口结构模式,(2)估计有效人口规模(Ne),(3)评估人口规模增长或下降的信号。利用核和线粒体DNA变异的数据,我们证明了这个物种形成了一个单一的,整个范围内的恐慌人口,没有证据表明任何部分人口历史上使用不同的迁徙途径。Further,使用合并估计,我们估计该人口的有效规模为数十万至数百万人。东部红蝙蝠种群的高水平基因流和连通性表明,对东部红蝙蝠的监测和管理必须整合该物种范围内的信息。
    Documented fatalities of bats at wind turbines have raised serious concerns about the future impacts of increased wind power development on populations of migratory bat species. However, for most bat species we have no knowledge of the size of populations and their demographic trends, the degree of structuring into discrete subpopulations, and whether different subpopulations use spatially segregated migratory routes. Here, we utilize genetic data from eastern red bats (Lasiurus borealis), one of the species most highly affected by wind power development in North America, to (1) evaluate patterns of population structure across the landscape, (2) estimate effective population size (Ne ), and (3) assess signals of growth or decline in population size. Using data on both nuclear and mitochondrial DNA variation, we demonstrate that this species forms a single, panmictic population across their range with no evidence for the historical use of divergent migratory pathways by any portion of the population. Further, using coalescent estimates we estimate that the effective size of this population is in the hundreds of thousands to millions of individuals. The high levels of gene flow and connectivity across the population of eastern red bats indicate that monitoring and management of eastern red bats must integrate information across the range of this species.
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