Outcrossing mating system of the early-divergent moonwort fern (Botrychium lunaria, Ophioglossaceae) revealed in the European Alps

Premise of the Research. Vascular plants depend on sexual recombination for generating new genetic variability to meet environmental needs. Nevertheless, members of the early-divergent fern genus Botrychium (Ophioglossaceae) typically maintain gametophytic selfing and show strong inbreeding within populations. To explain this evolutionary anomaly, the existence of previous or current but undiscovered outcrossing, genetically rich, precursors of the existing genetically depauperate taxa has been hypothesized. Methodology. Using allele expression at thirteen independently assorting enzyme loci, we compared allelic diversity and levels of heterozygosity in 471 Botrychium lunaria individuals across sixteen populations in the Alps and Jura Mountains of Switzerland. We examined habitat characteristics influencing mating systems and investigated population genetic structure based on a discriminant analysis of principal components and a graph-theoretic framework. We tested the pattern of is...研究背景：维管植物依赖有性重组以产生新的遗传变异，从而适应环境需求。然而，早期分化的蕨类属瓶尔小草属（Botrychium，瓶尔小草科Ophioglossaceae）的类群通常维持配子体自交，并在种群内表现出强烈的近交现象。为解释这一进化异常，学界已提出假说：现存遗传匮乏的类群，其此前或当前存在未被发现的、具有丰富遗传多样性的异交祖先类群。 研究方法：本研究利用13个独立分离的酶位点的等位基因表达信息，对瑞士阿尔卑斯山脉与汝拉山脉16个种群的471株扇羽阴地蕨（Botrychium lunaria）个体的等位基因多样性及杂合性水平进行了比较分析。我们考察了影响交配系统的生境特征，并基于主成分判别分析（discriminant analysis of principal components）与图论框架探究了种群遗传结构。我们检验了……的模式。