Data from: Microsatellite evidence for obligate autogamy, but abundant genetic variation in the herbaceous monocarp Lobelia inflata (Campanulaceae)

Although high levels of self-fertilization (>85%) are not uncommon in nature, organisms reproducing entirely through selfing are extremely rare. Predominant selfers are expected to have low genetic diversity because genetic variation is distributed among rather than within lineages, and is readily lost through genetic drift. We examined genetic diversity at 22 microsatellite loci in 105 individuals from a population of the semelparous herb Lobelia inflata L., and found (1) no evidence of heterozygosity through outcrossing, yet (2) high rates of genetic polymorphism (2-4 alleles per locus). Furthermore, this genetic variation among lineages was associated with phenotypic traits (e.g. flower colour, size at first flower). Coupled with previous work characterizing the fitness consequences of reproductive timing, our results suggest that temporal genotype-by-environment interaction may maintain genetic variation and, because genetic variation occurs only among lineages, this simple system offers a unique opportunity for future tests of this mechanism.尽管自然界中自交率高于85%的情况并不少见，但完全通过自交繁殖的生物体却极为罕见。人们普遍认为，主要以自交繁殖的类群遗传多样性较低，这是因为遗传变异分布于不同谱系之间而非谱系内部，且易通过遗传漂变而丢失。本研究对单次结实草本植物山梗菜（Lobelia inflata L.）种群的105个个体的22个微卫星位点（microsatellite loci）开展了遗传多样性检测，结果发现：(1) 未检测到异交产生杂合性的证据，(2) 却呈现出较高的遗传多态性水平（每个位点包含2-4个等位基因）。此外，谱系间的遗传变异与花色、首花大小等表型性状存在关联。结合此前关于繁殖时机对适合度影响的研究成果，本研究结果表明，时间尺度下的基因型-环境互作或许能够维持遗传多样性；又由于该系统的遗传变异仅存在于谱系之间，这一简易实验体系为未来验证该维持机制提供了独特的研究契机。