School of Plant Science, University of Tasmania Private Bag 55, Hobart, Tasmania, 7001, Australia ; Biological Sciences, University of Alberta Edmonton, Alberta, T6G 2E9, Canada.
Ecol Evol. 2012 Nov;2(11):2631-44. doi: 10.1002/ece3.376. Epub 2012 Sep 21.
Morphologically similar groups of species are common and pose significant challenges for taxonomists. Differences in approaches to classifying unique species can result in some species being overlooked, whereas others are wrongly conserved. The genetic diversity and population structure of the Pterostylis longifolia complex (Orchidaceae) in Tasmania was investigated to determine if four species, and potential hybrids, could be distinguished through genomic AFLP and chloroplast restriction-fragment-length polymorphism (RFLP) markers. Analysis of molecular variance (AMOVA) results indicated that little genetic variation was present among taxa, whereas PCoA analyses revealed genetic variation at a regional scale irrespective of taxa. Population genetic structure analyses identified three clusters that correspond to regional genetic and single taxon-specific phenotypic variation. The results from this study suggest that "longifolia" species have persisted throughout the last glacial maximum in Tasmania and that the complex may be best treated as a single taxon with several morphotypes. These results could have serious evolutionary and conservation implications as taxonomic changes could result in the instatement of a single, widespread taxon in which rarer morphotypes are not protected.
形态相似的物种群很常见，这给分类学家带来了重大挑战。在对独特物种进行分类的方法上存在差异，可能导致一些物种被忽视，而另一些物种则被错误地保护。本研究对塔斯马尼亚长叶兜兰复合体（兰科）的遗传多样性和种群结构进行了研究，以确定是否可以通过基因组 AFLP 和叶绿体限制性片段长度多态性（RFLP）标记来区分四个物种和潜在的杂种。分析分子方差（AMOVA）的结果表明，分类群之间存在的遗传变异很小，而 PCoA 分析显示，无论分类群如何，在区域尺度上都存在遗传变异。种群遗传结构分析确定了三个与区域遗传和单一分类群特有表型变异相对应的聚类。本研究的结果表明，“长叶”物种在塔斯马尼亚的最后一个冰河时代一直存在，并且该复合体最好被视为一个具有多种形态的单一分类群。这些结果可能具有严重的进化和保护意义，因为分类学的变化可能导致单一、广泛分布的分类群被建立，而其中较罕见的形态则不受保护。
