■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.