长江中下游地区菱属植物的DNA分子鉴别

目的 对野生菱和栽培菱种rDNA ITS片段进行分析，探讨该片段在两大群体中的系统学及鉴别研究意义。方法 对菱的rDNA ITS区进行了PCR扩增、测序，运用clustal、Mega 2．0等软件对ITs区进行序列分析鉴别。结果 获得rDNAI TS1、ITS2和5．8S rDNA完整序列，10个居群菱的ITS1与ITS2序列的长度分别为234～236 bp和220～221 bp，5．8S区均为164bp，不同居群的碱基差异为0．22％～2．94％。变异位点数为16个，信息位点数6个。用NJ法根据ITS序列数据构建系统发生树。结论 尽管菱属各居群间rDNA ITS的差异百分率较小，其亲缘关系较近，但根据ITS序列的特征可以很好地鉴别野生菱、栽培菱，菱属植物有可能都起源于同一种野生类居群。

Identification of Trapa L. plants along middle-low reaches of Changjiang River by analyzing their DNA sequences

Object To analyze the rDNA ITS sequences between wi ld plants and cultivars of Trapa L. and study the utility in p hylogenesis and identification of these two groups. Methods The ITS gene fragments were PCR amplified and sequenced. The rDNA ITS regions w ere analyzed by means of the software of Clustal and Mega 2.0. Result s The rDNA sequences of 234-236 bp ITS1, 220-221 bp ITS2 gene fragment , and 5.8 S rDNA for 164 bp evenly were obtained from ten populations of Trapa L. The intraspecific substitution varies from 0.22% to 2. 94%. The variable sites are 16 while informative sites are six. The phylogenet ic tree based on ITS data was set up by NJ method. Conclusion ITS sequence is a pretty good molecular marker which can identify wild plants of Trapa L. from their cultivars. Diversity of ITS in differen t populations is less at intraspecific level. It is infered that the plants of Trapa L. may be derived from the same population of one species .