运用ITS基因分析大鹏半岛海域石珊瑚系统发育关系

Phylogenetic Relationships in Scleractinian from Water of Dapeng Peninsula Based on ITS Genes

通过ITS基因特异扩增测序,对大鹏半岛海域46种石珊瑚ITS基因片段序列进行了比较分析。结果表明,该片段序列长度在674~806碱基对(bp)之间,A、T含量在40%~55.5%之间,大部分物种的序列碱基A、T含量小于G、C含量。46种造礁珊瑚的平均遗传距离为0.261。采用邻位连接(NJ)和最小进化(ME)法分别构建15种复合型珊瑚的5.8S r DNA系统发育树和28种坚实型珊瑚的ITS2系统发育树,结果显示15种复合型珊瑚的5.8S r RNA序列系统进化聚类结果较符合传统形态学分类结果,而28种坚实型珊瑚的ITS2序列系统进化聚类结果与传统形态学存在较大的差异,提示石珊瑚表型的变异性可能对传统分类存在影响。

Partial sequences of ITS from46species of scleractinian in water of Dapeng peninsula wereamplified and sequenced.Base ratio and genetic distances were analyzed.The result indicated that thesize of this region was between674–806bp,A+T contents of ITS fragments was between40%–55.5%,A+T contents of ITS fragments were less than G+C in the most species.The average geneticdistance was0.261from46species.The5.8S rDNA data was used to construct phylogeny trees of15species which belong to the complex-clade.The ITS2data was used to construct phylogeny trees of28species which belong to the robust-clade.According to the neighbour-joining and minimum-evolutiontrees of I5.8S rDNA and TS2datas,the phylogeny of28species which belong to the robust-clade wasconformed to morphological conclusion.However,the phylogeny of28species which belong to the robust-clade was hugely different from the morphological conclusion.The result suggested thatmorphological classification may be limited by coral skeletons plasticity.