Pelser Pieter B, Gravendeel Barbara, van der Meijden Ruud
Nationaal Herbarium Nederland, Universiteit Leiden, P.O. Box 9514, 2300 RA Leiden, The Netherlands.
Am J Bot. 2002 Jun;89(6):929-39. doi: 10.3732/ajb.89.6.929.
The molecular phylogeny of Senecio sect. Jacobaea (Asteraceae; Senecioneae) was studied to clarify species composition and interspecific relationships of Senecio sect. Jacobaea. This information is necessary for studies seeking explanations of the evolutionary success of Senecio, in terms of high species numbers and the evolution of chemical defense mechanisms. Parsimony analyses with 60 species of the tribe Senecioneae, representing 23 genera and 11 sections of Senecio, based on DNA sequence data of the plastid genome (the trnT-L intergenic spacer, the trnL intron, and two parts of the trnK intron, flanking both sides of the matK gene) and nuclear genome (ITS1, 5.8S, and ITS2 gene and spacers) show that sect. Jacobaea is a strongly supported monophyletic group. Fifteen species have been identified as members of section Jacobaea, including three species that have been consistently ascribed to this section in taxonomic literature and 12 species that were either placed in other sections of Senecio or not exclusively ascribed to sect. Jacobaea. This section was traditionally circumscribed as a group of European, biennial, or perennial herbs with pinnately incised leaves, but the results of this study show that one annual species, a species from northeastern Asia, and a species growing in the Himalayas are members of sect. Jacobaea as well. Furthermore, not all species in the section have pinnately incised leaves. The genera Emilia, Packera, and Pseudogynoxys form the sister clade of sect. Jacobaea, but this relationship lacks strong bootstrap support and thus remains provisional.
对千里光属（菊科；千里光族）的雅各布千里光组进行了分子系统发育研究，以阐明雅各布千里光组的物种组成和种间关系。这些信息对于那些试图从高物种数量和化学防御机制进化的角度来解释千里光进化成功原因的研究来说是必要的。基于质体基因组（trnT-L基因间隔区、trnL内含子以及trnK内含子两侧与matK基因侧翼的两个部分）和核基因组（ITS1、5.8S、ITS2基因及间隔区）的DNA序列数据，对代表千里光族23个属和11个组的60个物种进行简约分析，结果表明雅各布千里光组是一个得到有力支持的单系类群。已鉴定出15个物种为雅各布千里光组的成员，其中包括分类学文献中一直归属于该组的3个物种，以及曾被置于千里光属其他组或未完全归属于雅各布千里光组的12个物种。该组传统上被界定为一群具有羽状深裂叶的欧洲二年生或多年生草本植物，但本研究结果表明，一个一年生物种、一个来自亚洲东北部的物种以及一个生长在喜马拉雅地区的物种也是雅各布千里光组的成员。此外，该组并非所有物种都具有羽状深裂叶。一点红属、蜂斗菜属和假柄菊属构成了雅各布千里光组的姐妹分支，但这种关系缺乏有力的自展支持，因此仍为暂定关系。
