Ex-situ conservation is widely used to protect wild plant species from extinction. However, it remains unclear how genetic variation of ex-situ plant collections reflects wild source population diversity. Here, we conduct a global meta-analysis of the genetic representativeness of ex-situ populations by comparing genetic diversity (i.e. AR, allelic richness; HE , expected heterozygosity; PPB, percentage polymorphic bands; and SWI, Shannon-Winner index), inbreeding coefficient (FIS ), and genetic differentiation between ex-situ plant collections and their wild source populations. Genetic diversity (i.e., HE , PPB, and SWI) was significantly lower in ex-situ populations than their wild source populations, while genetic differentiation between ex-situ and wild populations (ex-situ-wild FST ), but not that among ex-situ populations, was significantly higher than among wild populations. Outcrossing species, but not those with mixed mating system, had significantly lower genetic diversity in ex-situ populations, and significantly higher ex-situ-wild FST . When the collection size for ex-situ conservation was ≥30 or 50, PPB, HE , and ex-situ-wild FST were not significantly different between ex-situ and wild populations, indicating a relatively high genetic representativeness. Collecting from the entire natural distribution range and mixing collections from different sources could significantly increase the genetic representativeness of ex-situ populations. Type of ex-situ conservation (i.e., planting or seed bank) had no effect on genetic representativeness. The effect size of HE decreased and the effect size of ex-situ-wild FST increased with the duration of ex-situ conservation. Our results suggest that current ex-situ plant collections do not effectively capture the genetic variation of wild populations. Low genetic representativeness of ex-situ populations was caused by both initial incomplete sampling from wild populations and genetic erosion during ex-situ conservation. We emphasize that it is necessary to employ more thorough sampling strategies in future collecting efforts and to add new individuals where needed. Article impact statement: Low genetic representativeness of living plant collections is a worldwide problem in ex situ conservation. This article is protected by copyright. All rights reserved.

中文翻译：

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异地保护下植物种群与野生来源种群遗传代表性的荟萃分析

异地保护被广泛用于保护野生植物物种免于灭绝。然而，目前尚不清楚异地植物收藏的遗传变异如何反映野生来源种群的多样性。在这里，我们通过比较遗传多样性（即 AR，等位基因丰富度；HE，预期杂合性；PPB，多态性带百分比；和 SWI，Shannon-Winner 指数），近交系数（FIS），以及易地植物收集物与其野生来源种群之间的遗传差异。迁地种群的遗传多样性（即 HE、PPB 和 SWI）显着低于其野生来源种群，而迁地种群与野生种群之间的遗传差异（ex-situ-wild FST），而不是迁地种群之间的遗传差异。 - 原地种群，明显高于野生种群。异交物种，但不是那些具有混合交配系统的物种，异地种群的遗传多样性显着较低，而异地野生 FST 显着较高。当迁地保护采集规模≥30或50时，迁地种群与野生种群之间的PPB、HE和迁地野生FST差异不显着，表明具有较高的遗传代表性。从整个自然分布范围收集并混合不同来源的收集可以显着增加迁地种群的遗传代表性。异地保护类型（即种植或种子库）对遗传代表性没有影响。HE的效应量随着迁地保护时间的延长而减小，而异地野生FST的效应量增加。我们的结果表明，当前的异地植物收集不能有效地捕捉野生种群的遗传变异。迁地种群的低遗传代表性是由于野生种群的初始采样不完整和迁地保护过程中的遗传侵蚀造成的。我们强调有必要在未来的收集工作中采用更彻底的抽样策略，并在需要时增加新的个体。文章影响声明：活植物收藏品的低遗传代表性是异地保护的世界性问题。本文受版权保护。版权所有。我们的结果表明，当前的异地植物收集不能有效地捕捉野生种群的遗传变异。迁地种群的低遗传代表性是由于野生种群的初始采样不完整和迁地保护过程中的遗传侵蚀造成的。我们强调有必要在未来的收集工作中采用更彻底的抽样策略，并在需要时增加新的个体。文章影响声明：活植物收藏品的低遗传代表性是异地保护的世界性问题。本文受版权保护。版权所有。我们的结果表明，当前的异地植物收集不能有效地捕捉野生种群的遗传变异。迁地种群的低遗传代表性是由于野生种群的初始采样不完整和迁地保护过程中的遗传侵蚀造成的。我们强调有必要在未来的收集工作中采用更彻底的抽样策略，并在需要时增加新的个体。文章影响声明：活植物收藏品的低遗传代表性是异地保护的世界性问题。本文受版权保护。版权所有。我们强调有必要在未来的收集工作中采用更彻底的抽样策略，并在需要时增加新的个体。文章影响声明：活植物收藏品的低遗传代表性是异地保护的世界性问题。本文受版权保护。版权所有。我们强调有必要在未来的收集工作中采用更彻底的抽样策略，并在需要时增加新的个体。文章影响声明：活植物收藏品的低遗传代表性是异地保护的世界性问题。本文受版权保护。版权所有。