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运用ITS2序列对木瓜及其近缘属植物进行DNA条形码分子鉴定,探讨利用ITS2条形码序列对木瓜及近缘物属植物鉴定的可行性。对试验样品进行DNA提取纯化、PCR扩增并双向测序得到22条ITS2序列,将所得22条序列和Gen Bank数据库下载的8条木瓜及其近缘植物的ITS2序列用Clustal X软件进行比对,Bio Edit软件人工校正;利用MEGA5.05软件计算种内、种间遗传距离,并采用K2P距离法构建NJ和ML树,评价序列的鉴定效果。木瓜及其近缘属植物种内遗传距离变异区间为0~0.0274,平均0.0029,木瓜及近缘属植物种间遗传距离变异区间为0.011~0.112,平均0.075,种间距离明显大于种内距离;构建木瓜及其近缘属各物种NJ和ML系统进化树,二者结果一致,各物种均聚为一支,形成单系类群,支持率均在50%以上。ITS2条形码序列能够快速准确地鉴定木瓜属及其近缘属植物。
ITS2 sequence was used to identify DNA barcode molecules in papaya and its related genera, and to explore the feasibility of using ITS2 barcode sequence to identify papaya and its related genera. Twenty-two ITS2 sequences were obtained by PCR amplification and two-way sequencing. The sequences of 22 ITS2 sequences from eight quinces and their relatives downloaded from Gen Bank database were compared by Clustal X software. Bio Edit software was used for manual calibration. MEGA5.05 software was used to calculate intraspecific and interspecific genetic distances. NJ and ML trees were constructed by K2P distance method to evaluate the sequence identification. The genetic distance variation range of Papaya and its related genera was 0 ~ 0.0274 with an average of 0.0029. The variation range of genetic distance between papaya and its related species was 0.011 ~ 0.112, with an average of 0.075. The interspecific distance was significantly greater than the intraspecific distance. The phylogenetic tree of NJ and ML phylogeny of papaya and its related species was constructed. The two results were consistent, and all the species clustered together to form monophyletic groups with the support rate above 50%. ITS2 barcode sequence can quickly and accurately identify Chaenomeles and their related genera.