Isozyme variation and ploidy levels within the apomictic Ranunculus auricomus complex:: Evidence for a sexual progenitor species in southeastern Austria
Isozyme variation and ploidy levels within the apomictic Ranunculus auricomus complex:: Evidence for a sexual progenitor species in southeastern Austria
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DOI：
10.1055/s-2000-9148
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发表时间：
2000-01-01
期刊：
影响因子：
3.9
通讯作者：
Dobes, C
中科院分区：
文献类型：
--
作者：
Hörandl, E;Greilhuber, J;Dobes, C
通过水平淀粉凝胶电泳研究了二倍体物种Ranunculus notabilis 和主要无融合生殖R. auricomus 复合体的四倍体R. variabilis 的三个群体中的每一个中11种酶的同种异位酶变异。电泳模式的遗传解释得到染色体计数和光密度倍性水平测定的支持。 R, notabilis 被确认为二倍体 (2n = 16)，R. variabilis 被确认为四倍体 (2n = 32)。两个三倍体和一个四倍体个体被选为假定的杂种，计算了 13 个多态位点的基于等位基因频率和基因型频率的遗传变异性测量。 R. notabilis 的等位基因和基因型变异与其他有性植物相似，并且该物种被证明是远交系而非二单倍体无融合生殖体。 R. variabilis 的相应值证实了先前假设的克隆种群结构。在 R. variabilis 中观察到的杂合子频率较高，表明其杂交起源和缺乏减数分裂。假定的杂交体显示出两个物种的形态表型和电泳模式的组合。物种间遗传同一性很高（0.905），但仍低于物种内部（R. notabilis：0.965，R. variabilis：0.940）；相应的距离值可以在树状图中清楚地区分两个物种。R. notabilis 和 R. variabilis 之间的遗传同一性和距离值与其他祖先-衍生物种对相似。结果支持这样的假设：R. notabilis 是 R. auricomus 复合体的一种古老有性物种，也是可能的异源多倍体 R. variabilis 的祖先之一。
Allozyme variation of 11 enzymes in each of three populations of the diploid species Ranunculus notabilis and the tetraploid R. variabilis of the predominantly apomictic R. auricomus complex has been studied by horizontal starch gel electrophoresis. Genetic interpretation of electrophoretic patterns is supported by chromosome counts and densitometric ploidy level determination. R, notabilis is confirmed as diploid (2n = 16), and R. variabilis as tetraploid (2n = 32). Two triploids and one tetraploid individual were sorted out as putative hybrids, Genetic variability measures based on both allelic frequencies and genotype frequencies were calculated for 13 polymorphic loci. Allelic and genotypic variation in R. notabilis is similar to other sexual plants, and the species is shown to be an outbreeder and not a dihaploid apomict. Corresponding values in R. variabilis confirm a previously assumed clonal population structure. A higher frequency of observed heterozygotes in R. variabilis indicates its hybridogenous origin and the lack of meiosis. Putative hybrids showed combinations of morphological phenotype and electrophoretic patterns of both species. Genetic identity is high among species (0.905), but still lower than within species (R. notabilis: 0.965, R. variabilis: 0.940); corresponding distance values allow a clear separation of the two species in a dendrogram, Genetic identity and distance values between R. notabilis and R. variabilis resemble those of other progenitor-derivative species pairs, The results favour the hypothesis that R. notabilis is an ancient sexual species of the R. auricomus complex and also one progenitor of the presumably allopolyploid R. variabilis.