方斑网衣的分子鉴定和系统发育学分析

为鉴定方斑网衣中的隐存种,以新疆地区的方斑网衣为试验材料,用分子系统发育学方法,研究了方斑网衣核糖体DNA内转录间隔区(internal transcribed spacer,ITS)碱基组成信息、变异位点以及简约信息位点、种内的遗传距离、遗传距离聚类情况、ITS位点系统发育树分析以及基于条形码间隔自动检索鉴定方斑网衣隐存种类。结果表明:方斑网衣ITS基因片段长度为528 bp,其中62个为变异位点、43个为简约位点、460个为保守位点、G+C碱基组成占总含量的56.1%、G+C含量高于A+T含量、单倍型多样性(haplotype(gene)diversity,Hd)为0.993、核酸多样性(nucleotide diversity,Pi)为0.048 76;基于遗传距离构建的聚类树同系统发育树分支聚类情况一致,分为2个大分支;通过条形码自动检索法鉴定出方斑网衣可为2个种。通过综合分析鉴定出方斑网衣2个隐存种即方斑网衣原种(Lecidea tessellata var.tessellata)和方斑网衣蓝变种(Lecidea tessellata var.caesia)。

Molecular Identification and Phylogenetic Analysis of Lecidea tessellata

In order to indentify cryptic species within Lecidea tessellata,the specimensof Lecidea tessellatadistributed in Xinjiang were seleted as materials.The internal transcribed spacer(ITS)of L.tessellata was amplified specifically to be used for molecular analyses.The cluter analysis of the genetic distances,automatic barcode gap discovery and molecular phylogenies were studied.The results showed that the length of ITS gene fragment was 528 bp,including 62 variation sites,43 reduced sites and 460 conserved sites.The G+C base composition accounted for 56.1%of the total content,and G+C content was higher than A+T content.Haplotype(gene)diversity(Hd)was 0.993,and nucleotide diversity(Pi)was 0.048 76.The topologies of the molecular phylogenies and cluter based on genetic distances were coincident which fell into two clades,and they were identified as two species by the automatic barcode gap discovery approach.The results indicated that there were two species which identified Lecidea tessellata var.tessellata and Lecidea tessellata var.caesia.