Hybridisation and genetic diversity in introduced Mimulus (Phrymaceae)
Hybridisation and genetic diversity in introduced Mimulus (Phrymaceae)
复制标题
引入的酸浆草（Phrymacaceae）的杂交和遗传多样性
作者：
Mario Vallejo;G. Lye
具有不同倍性水平的分类群之间的杂交通常与杂交不育有关。克隆繁殖可以稳定这些杂交种，但普遍存在的克隆可能会对自然种群中遗传多样性的分布产生深远的影响。在这里，我们调查了一个广泛存在的三倍体分类群，它是由二倍体滴虫和四倍体黄鼠杂交产生的，这两个物种在19世纪被引入英国。这种名为Mimulus x robertsii的杂交种在很大程度上是不育的，但能够多产无性繁殖，自1872年以来一直在野外记录。我们调查了来自英国各地的40个Mimulus种群，以检查当前杂交种的发生率，并选择了17个种群使用共显性标记进行遗传分析。聚类分析揭示了两组主要的遗传差异个体，对应于二倍体(M.guttatus)或多倍体(M.luteus和M.x robertsii)样本。约50%的采样点发现了三倍体杂交种，有时与亲本种之一共存。另一位父母是黄种分枝杆菌，被限制在一个地方。罗氏田鼠的个体种群具有遗传多样性，包含多个高度杂合的克隆，大多数遗传变异分布在种群之间，而不是种群内。我们的发现表明，这种在很大程度上不育的克隆分类群可以保存不可忽略的遗传变异。遗传变异的杂交种群的存在可能为无性类群在不同环境中的持续成功提供材料。
Hybridisation among taxa with different ploidy levels is often associated with hybrid sterility. Clonal reproduction can stabilise these hybrids, but pervasive clonality may have a profound impact on the distribution of genetic diversity in natural populations. Here we investigate a widespread triploid taxon resulting from hybridisation between diploid Mimulus guttatus and tetraploid Mimulus luteus, two species that were introduced into the United Kingdom (UK) in the nineteenth century. This hybrid, Mimulus x robertsii, is largely sterile but capable of prolific vegetative propagation and has been recorded in the wild since 1872. We surveyed 40 Mimulus populations from localities across the UK to examine the current incidence of hybrids, and selected seventeen populations for genetic analysis using codominant markers. Cluster analyses revealed two main groups of genetically distinct individuals, corresponding to either diploid (M. guttatus) or polyploid (M. luteus and M. x robertsii) samples. Triploid hybrids were found in around 50% of sampled sites, sometimes coexisting with one of the parental species (M. guttatus). The other parent, M. luteus, was restricted to a single locality. Individual populations of M. x robertsii were genetically variable, containing multiple, highly heterozygous clones, with the majority of genetic variation distributed among- rather than within populations. Our findings demonstrate that this largely sterile, clonal taxon can preserve non-negligible amounts of genetic variation. The presence of genetically variable hybrid populations may provide the material for the continued success of asexual taxa in diverse environments.
影响因子：
3.3
作者：
L. Excoffier;P. Smouse;J. Quattro
通讯作者：
L. Excoffier;P. Smouse;J. Quattro