南川绣线菊和细枝绣线菊分子水平研究

摘要

36 individuals in total from 6populations ( Spiraea rosthornii, 3; Spiraea myrtilloides, 3 ) were sampled for sequence analysis to carry out a preliminary study. Total genomic DNA was extracted from silica gel-dried leaves following the CTAB method and used as the template in the polymerase chain reaction (PCR) . The trnL-F intergenic spacer was chosen to be amplified and sequenced in all individuals. 3 chloroplast haplotypes ( Rosl -Ros3 ) were identified by the analysis of cpDNA variation from Spiraea rosthornii, 2 chloro-plast haplotypes ( Myrl-Myr2) from Spiraea myrtilloides. The total alignment of the sequences was 850 bp in length. These sequences included 9 polymorphic sites (0. 11% ). 8 of them were caused by substitution mutations and the other one caused by indels. The result of gene diversity analysis indicated significantly phylogeographic pattern within the entire distribution range. Maximum Likelihood (ML) phylogenetic trees, Maximum Parsimony (MP) phylogenetic trees and a BI multi-Locus phylogenetic tree of the 5 cpDNA haplotypes detected from the 36 individuals were recovered from the heuristic search, using Rosa californica and Sorbaria sorbifolia as out-groups. Distinct topology trees were detected indicating that morphology discrepancy is consonant with this at the molecular level for the two species. Gene diversity analysis suggested that cpDNA trnL-trnY sequence is availability for molecular phylogeography of Spiraea.%对6个野外居群(南川绣线菊和细枝绣线各3个)36个个体进行叶绿体(chloroplast,cp)DNA trnL-trnF片断测序分析.在南川绣线菊中发现了3个单倍型(Ros1-Ros3),在细枝绣线菊中发现了2个单倍型(Myr1-Myr2).两个种的序列联合分析对位排列后得到850 bp,共有9个变异位点,其中一个为碱基插入或缺失,另外8个为碱基置换,变异位点的百分率为0.11.对单倍型的遗传多样性分析表明同一区域亲缘关系相近的单倍型发生于同一居群中,并且存在着明显的分子系统地理学关系.以蔷薇科另两个外属植物Rosa californica 和 Sorbaria sorbifolia为外类群构建这两个种的最大简约(MP)树、最大似然(ML)树及贝叶斯树,结果获得了分辨良好的种间关系树.这表明在分子水平上两个种之间存在明显的差异,这与形态学上的表现是相一致的.遗传多样性分析结果表明了cpDNA trnL-trnF 片段对于绣线菊属的分子地理学研究还是比较有效的,可以通过进一步的大面积采样和分析来揭示植物的遗传结构、冰期避难所等问题.