几条热点 DNA 条形码序列对海南大戟科植物鉴定能力比较

    Comparison of the Ability of Several Regions as DNA Barcode for Identifying Euphorbiaceae in Hainan

    • 摘要: 【目的】比较 ITS2、ITS、psbA-trnH、rbcL、matK 序列对海南大戟科植物的鉴定能力。【方法】利用 PCR 测序法对供试样本目的片段进行双向测序,所得序列经 Codon Code Aligner 拼接后,利用 MEGA 6.0 进行相关数据分析,利用 TAXON DNA 软件分析序列种内、种间变异并作 barcoding gap 分析。【结果】5 条候选序列的序列获得率分别为 86.96%、76.81%、89.86%、79.71%、49.28%;ITS2 序列的变异系数和信息位点系数最大;ITS2 序列存在明显的 barcoding gap,种间与种内变异分布呈两边分开的趋势。ITS 序列虽存在 barcoding gap,但种内变异和种间变异有较多的重叠区;psbA-trnH 和 matK 序列 barcoding gap 均不明显,同时种内变异和种间变异有较多的重叠区;rbcL 序列虽 barcoding gap 不明显,但种内变异和种间变异重叠比例较小。【结论】ITS2 条形码序列对海南大戟科植物鉴定能力强,rbcL 序列不能作为单独的条形码鉴定物种,但可以作为 ITS2 的补充条形码。

       

      Abstract: 【Objective】The identification ability of ITS2, ITS, psbA-trnH,rbcL, matK sequences to Euphorbiaceae plants in Hainan was compared.【Method】Bidirectional sequencing was conducted on the target sequence of the test sample by PCR sequencing. Sequence assembly and consensus sequence generation were performed by using Codon Code Aligner. Phylogenetic study was performed by using software MEGA 6.0 in accordance with Kimura-2-parameter (K2P) mode. The distribution of intra-specific and inter-specific variation was analyzed by TAXON DNA software and analysis on DNA barcoding gaps was carried out.【Result】The sequence acquisition rates of the five candidate sequences were 86.96%, 76.81%, 89.86% , 79.71% and 49.28%, respectively. The coefficient of variation and information site coefficient of ITS2 sequence were the largest. ITS2 sequence had obvious barcoding gap, and the distribution of interspecific and intraspecific variation tended to be separated on both sides. Although its sequence had barcoding gap, there were more overlap regions between intraspecific variation and interspecific variation. The barcoding gap of psbA-trnH and matK sequences was not obvious, and there were more overlap regions between intraspecific variation and interspecific variation; while the barcoding gap of rbcL sequence was not obvious, but the overlap ratio between intraspecific variation and interspecific variation was small.【Conclusion】ITS2 has strong ability to identify the Euphorbiaceae plants in Hainan, while rbcL can not be used as a single DNA barcode to identify species, but it can be used as a supplementary for ITS2.