High level of polymorphism and spatial structure in a selfing plant species, Medicago truncatula (Leguminosae), shown using RAPD markers
High level of polymorphism and spatial structure in a selfing plant species, Medicago truncatula (Leguminosae), shown using RAPD markers
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DOI：
10.1002/j.1537-2197.1996.tb12776.x
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发表时间：
1996-07
影响因子：
3
通讯作者：
I. Bonnin;T. Huguet;M. Ghérardi;J. Prosperi;I. Olivieri
中科院分区：
文献类型：
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作者：
I. Bonnin;T. Huguet;M. Ghérardi;J. Prosperi;I. Olivieri
使用 RAPD 标记和一个形态学标记，我们研究了一种自交一年生植物——蒺藜苜蓿 GAERTN 的群体间和群体内结构。从四个种群（每个种群又分为三个亚种群）中抽取大约 200 个人，对 22 个标记进行了评分。结果发现，群体内方差分量占总方差的55%，群体间方差分量占45%。总方差的 18% 是由于群体内部结构（即亚群体之间）造成的。因此，总方差的 37% 存在于亚群体内。使用多位点方法，发现两个群体没有共同的多位点基因型。四个研究群体中的两个由少量 (?6) 多位点基因型组成，而另外两个群体则由许多 (?15) 多位点基因型组成。在多态性最多的群体（37 种基因型）中，仅发现一种基因型为两个亚群体所共有。重采样实验表明，根据群体的不同，3 至 16 个多态位点对于对群体中的所有多位点基因型进行评分是必要且足够的。当将这些数据与已发表的结果进行比较时，似乎在某些情况下，自交物种每个种群的基因型数量可能大于仅考虑有效种群规模的预期。在某些种群中观察到的较大的亚种群内遗传差异可以通过亚种群内较小的邻域大小或通过种子和/或花粉迁移后的异型杂交来解释。
Using RAPD markers and one morphological marker, we studied the among- and within-population structure in a selfing annual plant species, Medicago truncatula GAERTN. About 200 individuals, sampled from four populations subdivided into three subpopulations each, were scored for 22 markers. It was found that the within-population variance component accounted for 55% of the total variance, while the among-population variance component accounted for 45%. Eighteen percent of the total variance was due to within-population structure (i.e., among subpopulations). Thus, 37% of the total variance was within subpopulations. Using a multilocus approach, it was found that no multilocus genotype was common to two populations. Two of the four studied populations were composed of few (?6) multilocus genotypes, whereas the other two had many (?15) multilocus genotypes. In the most polymorphic population (37 genotypes), only one genotype was found to be common to two subpopulations. Resampling experiments show that, depending on the population, three to 16 polymorphic loci were necessary and sufficient to score all multilocus genotypes in the population. When these data are compared to published results, it appears that on some occasions, the number of genotypes per population of selfing species might be larger than would be expected from the sole consideration of effective population size. The large within-subpopulation genetic variance observed in some populations could be explained by either small neighborhood sizes within subpopulations, or by outcrossing following migration through seed and/or pollen.