南方红豆杉谱系地理学研究

Phylogeographical Study on Taxus wallichiana var. mairei(Lemée & Léveillé) L.K.Fu & Nan Li

通过对南方红豆杉18个居群499个个体叶绿体基因组的trnL-F片段进行RFLP分析,共检测到6个叶绿体DNA单倍型,其中除台湾居群外的17个居群都包含有单倍型H1和H2;黄山及临安居群除单倍型H1、H2外,还分别各有1个特有单倍型。谱系关系分析显示,单倍型H1、H2为较古老的祖先单倍型。AMOVA分析显示,变异主要存在于居群内,居群间的遗传分化程度较低(26.39%)。嵌套分支分析(NCA)显示,单倍型分布与地理分布存在轻度的地理相关性,南方红豆杉现在的遗传结构可能源于居群的片段化效应,台湾居群可能是由于曾经的居群片段化而隔离或长距离扩散所致;在第四纪冰期,中国东、南部地区可能存在2个以上南方红豆杉的避难所。

Taxus wallichiana var.mairei （Lemée ＆ Léveillé） L.K.Fu ＆ Nan Li is a highly endangered conifer,a total of six haplotypes were detected in all 499 individuals of 18 populations,in chloroplast DNA trnL-F fragment by PCR-RFLP.H1 and H2 existed in all the populations distributing in mainland of China,but H3 only existed in Huangshan population,and H4 only existed in Lin’an population,with H5 and H6 coexisting in Taiwan population.The phylogeographic analysis suggested the H1 and H2 were the ancestor haplotypes,while the other haplotypes were evolved from them.Some 26.39% of the total variation existed among the populations,while 73.61% in the populations suggested by AMOVA.NCA analysis suggested there was slight correlation between the distribution of cpDNA haplotypes and geography,and the genetic structure of T.wallichiana var.mairei resulted from the effect of population fragment or the long-distance colonisation.Variation of cpDNA haplotypes suggested several glacial refugiums of T.wallichiana var.mairei in the east and south of China.