中国帘蛤目16种经济贝类DNA条形码及分子系统发育的研究

DNA barcoding and molecular phylogeny of 16 species of economical shellfish in Veneroida along China Coast

对中国帘蛤目主要经济贝类的分子系统发育进行了研究,应用DNA条形码通用引物扩增了6种中国近海帘蛤目经济贝类共计60个个体的COI基因片段,与GenBank收录的10种帘蛤目贝类50条同源序列进行比对。结果表明:帘蛤目贝类COI基因存在碱基插入和缺失现象,在16个物种中有6个物种存在103个插入和缺失位点,其中杂色蛤仔Ruditapes variegata、裂纹哥特蛤Katelysia hiantina插入和缺失位点均为30个,大竹蛏Solen grandis为27个;碱基的组成出现偏倚现象,A+T含量(64.2%)明显高于G+C含量(35.8%);基于K2P模型的计算,16个物种的种内平均遗传距离为0.010 6,种间平均遗传距离为0.388 4,后者是前者的21.34倍;系统发育树聚类分析表明,COI基因在科、属、种水平上的鉴定及其系统进化关系重构方面与传统的形态学分类一致性较高。研究表明,线粒体COI基因作为帘蛤目贝类DNA条形码在物种鉴定的适用性上提供了一定的依据,同时也为形态分类系统提供了必要补充。

Mitochondrial COI genes were sequenced from 60 individuals of 6 common species in Veneroida along China coast using the universal barcoding primers, and the 60 sequences were compared with the other 50 homolo- gous sequences from 10 shellfish species in Veneroida derived from the GenBank. The results showed that there were Insert-Deletion （indel） sites in many COI sequences in Veneroida species, total indel sites were 103, inclu- ding COI sequence indels of up to 30 for Manila clam Ruditapes variegate and Katelysia hiantina, and 27 for Solen grandis. On average, the content of A＋T（64. 2% ） was found significantly higher than that of G＋C （35.8%）. The Kimera-2-parameter model indicated that there was mean distances of 0. 388 4 in pairwise-species and 0. 010 6 in species. According to maximum parsimony and neighbor joining trees for all 110 sequences of Veneroi- da, there was very high consistency between molecular analysis and morphological classification on family, genus, and species levels. Consequently, the findings provided essential revision and supplement to morphology taxonomy.