The genetic structure of five populations of the tetraploid fern Asplenium trichomanes subsp. quadrivalens in northern Switzerland was analyzed. Asplenium trichomanes subsp. quadrivalens is one of the most common and most widespread ferns in Europe. In this study we have combined genetic investigations, spatial autocorrelation, and breeding experiments to investigate in detail five populations from natural rock faces. Enzyme electrophoresis revealed very low genetic variability within and among the populations. The small amount of variation was partitioned mainly among the localities, indicated by high Fst values up to 0.764. Overall means of the proportion of polymorphic loci ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\overline{P}=0.076$$ \end{document} ), the mean number of alleles per locus ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\overline{A}=1.086$$ \end{document} ), and the mean expected heterozygosity ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\overline{H}=0.018$$ \end{document} ) were low compared with other ferns (e.g., Kirkpatrick et al. 1990). Very few heterozygous individuals were found. Values of the fixation index (F) were high, ranging between 0.732 and 1.000 and indicating substantial inbreeding. Spatial autocorrelation showed different patterns of substructure in populations of A. trichomanes subsp. quadrivalens with a tendency for patches in short distances (up to 1.5 m). The breeding experiments with isolated prothalli and prothalli pairs showed that a mean of 56.4% of the isolated prothalli were successful in sporophyte formation. The highest rate in one population was 83.3%. We conclude that genetic load must be low in A. trichomanes subsp. quadrivalens. Sporophyte formation was statistically more successful in the experiments with gametophyte pairs than in isolates, indicating that additional cross‐fertilization occurred. The latter agreed with the occurrence of few heterozygote samples and the small number of multilocus phenotypes found in natural habitats. Asplenium trichomanes subsp. quadrivalens is shown to be a highly inbreeding taxon with the capability of single spore colonization and subsequent founding of new populations. Such features can be hypothesized to have contributed to the postglacial colonization and the widespread distribution of this taxon in Europe.

中文翻译：

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FernAsplenium trichomanessubsp.quadrivalens的遗传变异、种群结构和育种系统的研究

四倍体蕨类植物 Asplenium trichomanes subsp. 的五个种群的遗传结构。分析了瑞士北部的quadrivalens。Asplenium trichomanes subsp。quadrivalens 是欧洲最常见和最普遍的蕨类植物之一。在这项研究中，我们结合了遗传调查、空间自相关和育种实验，详细调查了来自天然岩壁的五个种群。酶电泳显示种群内部和种群之间的遗传变异性非常低。少量的变化主要分布在地点之间，由高达 0.764 的高 Fst 值表明。和平均预期杂合度（ \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp } \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2 } \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\overline{H}= 0.018$$ \end{document} ) 与其他蕨类植物相比较低（例如 Kirkpatrick et al. 1990）。很少发现杂合个体。固定指数 (F) 的值很高，介于 0.732 和 1.000 之间，表明存在大量近亲繁殖。空间自相关在 A. trichomanes subsp. 种群中显示出不同的亚结构模式。具有短距离（最多 1.5 m）斑块趋势的四星体。用分离的原体和原体对的育种实验表明，平均56.4%的分离原体在孢子体形成方面是成功的。某一人群的最高比率为 83.3%。我们得出结论，A. trichomanes subsp. 中的遗传负荷必须很低。四叶草。在配子体对实验中，孢子体形成在统计学上比在分离物中更成功，表明发生了额外的交叉受精。后者同意少数杂合子样本的发生和在自然栖息地中发现的少量多位点表型。Asplenium trichomanes subsp。Quadrivalens 被证明是一种高度近亲繁殖的分类群，具有单孢子定殖和随后建立新种群的能力。可以假设这些特征促成了冰后殖民化和该分类群在欧洲的广泛分布。