Wang X Q, Tank D C, Sang T
Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Mol Biol Evol. 2000 May;17(5):773-81. doi: 10.1093/oxfordjournals.molbev.a026356.
In Pinaceae, the chloroplast, mitochondrial, and nuclear genomes are paternally, maternally, and biparentally inherited, respectively. Examining congruence and incongruence of gene phylogenies among the three genomes should provide insights into phylogenetic relationships within the family. Here we studied intergeneric relationships of Pinaceae using sequences of the chloroplast matK gene, the mitochondrial nad5 gene, and the low-copy nuclear gene 4CL. The 4CL gene may exist as a single copy in some species of Pinaceae, but it constitutes a small gene family with two or three members in others. Duplication and deletion of the 4CL gene occurred at a tempo such that paralogous loci are maintained within but not between genera. Exons of the 4CL gene have diverged approximately twice as fast as the matK gene and five times more rapidly than the nad5 gene. The partition-homogeneity test indicates that the three data sets are homogeneous. A combined analysis of the three gene sequences generated a well-resolved and strongly supported phylogeny. The combined phylogeny, which is topologically congruent with the three individual gene trees based on the Templeton test, is likely to represent the organismal phylogeny of Pinaceae. This phylogeny agrees to a certain extent with previous phylogenetic hypotheses based on morphological, anatomical, and immunological data. Disagreement between the previous hypotheses and the three-genome phylogeny suggests that morphology of both vegetative and reproductive organs has undergone convergent evolution within the pine family. The strongly supported monophyly of Nothotsuga longibracteata, Tsuga mertensiana, and Tsuga canadensis on all three gene phylogenies provides evidence against previous hypotheses of intergeneric hybrid origins of N. longibracteata and T. mertensiana. Divergence times of the genera were estimated based on sequence divergence of the matK gene, and they correspond well with the fossil record.
在松科中，叶绿体基因组、线粒体基因组和核基因组分别通过父系、母系和双亲遗传。研究这三个基因组之间基因系统发育的一致性和不一致性，应该能够深入了解该科内部的系统发育关系。在这里，我们使用叶绿体matK基因序列、线粒体nad5基因序列和低拷贝核基因4CL，研究了松科的属间关系。4CL基因在松科的某些物种中可能以单拷贝形式存在，但在其他物种中它构成了一个由两到三个成员组成的小基因家族。4CL基因的复制和缺失发生的速度使得旁系同源位点在属内得以保留，但在属间则不然。4CL基因的外显子分歧速度大约是matK基因的两倍，是nad5基因的五倍。分区同质性检验表明这三个数据集是同质的。对这三个基因序列进行联合分析，生成了一个解析良好且得到有力支持的系统发育树。基于Templeton检验，联合系统发育树在拓扑结构上与三个单独的基因树一致，很可能代表了松科的生物系统发育。这个系统发育在一定程度上与先前基于形态学、解剖学和免疫学数据的系统发育假设一致。先前的假设与三基因组系统发育之间的不一致表明，松科营养器官和生殖器官的形态都经历了趋同进化。在所有三个基因系统发育树上，长苞铁杉、红皮云杉和加拿大铁杉得到有力支持的单系性，为反对先前关于长苞铁杉和红皮云杉属间杂交起源的假设提供了证据。基于matK基因的序列分歧估计了各属的分化时间，它们与化石记录吻合得很好。
