Lang Annick S, Gehrmann Thies, Cronberg Nils
Department of Biology, Lund University, Lund, Sweden.
Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands.
Front Plant Sci. 2021 Apr 7;12:517547. doi: 10.3389/fpls.2021.517547. eCollection 2021.
Among plants, gender dimorphism occurs in about 10% of all angiosperms and more than 50% of all moss taxa, with dwarf males (DM) found exclusively in some unisexual mosses. In this study, we explore the role of male dwarfism as a reproductive strategy in the widespread acrocarpous moss , which has facultative male dwarfism, having both dwarf males (DMs) and normal-sized males (NMs). We retrieved 119 SNP markers from transcriptomes which were used to genotype 403 samples from 11 sites at seven localities in southern Sweden. Our aims were to compare the genetic variability and genetic structure of sexually reproducing populations at different geographic levels (cushion, site, and locality) and compare in particular the relative contribution of females, dwarf males and normal-sized males to the observed genetic diversity. The numbers of DMs differed strongly between sites, but when present, they usually outnumbered both females and NMs. Low genetic differentiation was found at locality level. Genetic differentiation was strongest between cushions for females and NMs and within cushions for DMs indicating small scale structuring and sometimes inbreeding. NMs were more clonal than either DMs or females. Genetic diversity was similar between females and DMs, but lower for NMs. Two haplotypes were shared between females and DMs and one haplotype was shared between a DM and a NM. In conclusion, our results show that DMs and NMs play different roles in reproduction, inbreeding may occur at cushion level, but gene flow is high enough to prevent substantial genetic drift.
在植物中，性别二态性出现在约10%的被子植物和超过50%的苔藓类群中，矮小雄性（DM）仅在一些单性苔藓中被发现。在本研究中，我们探讨了雄性矮化作为一种繁殖策略在广泛分布的顶蒴藓类中的作用，这种苔藓具有兼性雄性矮化现象，既有矮小雄性（DM）又有正常大小的雄性（NM）。我们从转录组中检索了119个单核苷酸多态性（SNP）标记，用于对来自瑞典南部七个地区11个地点的403个样本进行基因分型。我们的目的是比较不同地理水平（垫状体、地点和地区）有性繁殖种群的遗传变异性和遗传结构，特别是比较雌性、矮小雄性和正常大小雄性对观察到的遗传多样性的相对贡献。矮小雄性的数量在不同地点之间差异很大，但一旦出现，它们的数量通常超过雌性和正常大小雄性。在地区水平上发现遗传分化较低。雌性和正常大小雄性在垫状体之间的遗传分化最强，而矮小雄性在垫状体内的遗传分化最强，这表明存在小规模结构，有时还存在近亲繁殖。正常大小雄性比矮小雄性或雌性更具克隆性。雌性和矮小雄性之间的遗传多样性相似，但正常大小雄性的遗传多样性较低。雌性和矮小雄性共享两种单倍型，一个矮小雄性和一个正常大小雄性共享一种单倍型。总之，我们的结果表明，矮小雄性和正常大小雄性在繁殖中发挥不同作用，垫状体水平可能发生近亲繁殖，但基因流足够高以防止大量遗传漂变。
