Weller S J, Friedlander T P, Martin J A, Pashley D P
Department of Entomology, Louisiana State University, Baton Rouge 70803.
Mol Phylogenet Evol. 1992 Dec;1(4):312-37. doi: 10.1016/1055-7903(92)90007-4.
The selection of exemplars has been shown both theoretically and empirically to affect tree topology, but the importance of the number and nature of taxa used to represent higher taxonomic lineages in molecular studies is rarely stressed. In our rRNA study of higher moths and butterflies (Lepidoptera: Ditrysia), the selection of different exemplars and outgroups caused major tree rearrangements. We also examined the effectiveness with which conserved rRNA regions track the diversification of Lepidoptera. Homoplasy is as prevalent at the few variable sites of conserved regions (18E, 18J, 28F) as at the many variable sites of a more rapidly evolving region (28B). Finally, 28B sequence variation differs qualitatively among lepidopteran superfamilies of presumed comparable age, the Papilionoidea (true butterflies) and Noctuoidea (cutworm moths and relatives).
理论和实证研究均表明，模式标本的选择会影响系统发育树的拓扑结构，但在分子研究中，用于代表更高分类谱系的分类单元数量和性质的重要性却很少受到强调。在我们对高等蛾类和蝶类（鳞翅目：双孔次目）的rRNA研究中，不同模式标本和外类群的选择导致了系统发育树的重大重排。我们还研究了保守rRNA区域追踪鳞翅目多样化的有效性。在保守区域（18E、18J、28F）的少数可变位点上，同塑性与进化较快区域（28B）的许多可变位点一样普遍。最后，在假定年龄相当的鳞翅目超科——凤蝶总科（真蝶类）和夜蛾总科（夜蛾及其近缘类群）中，28B序列变异在质量上存在差异。
