巨蛎属牡蛎DNA序列的比较及鉴定

【目的】了解巨砺属牡蛎的系统关系和种类区分。【方法】对我国沿海分布的7种巨砺属牡蛎(香港牡蛎、有明牡蛎、熊本牡蛎、岩牡蛎、艾氏牡蛎、太平洋牡蛎、葡萄牙牡蛎)的线粒体DNA片段(COI、12S、16S和tRNAs),以及核糖体RNA基因转录间隔子序列(ITS-1、ITS-2和ITS)进行分子系统学研究。【结果】无论种间或种内,tRNAs序列差异最大,亚种内TS1序列差异最大;tRNAs和COI序列较其它序列变异更快,种间变异与种内变异之间有明显的条形码间隙;12S、16S、ITS和ITS2的种间变异与种内变异无重叠及条形码间隙;ITS1的种间变异与种内变异出现重叠。在亚种层面,12S、ITS、ITS1和ITS2的亚种间变异与亚种内变异出现重叠;16S的亚种间变异与亚种内变异无重叠及条形码间隙;tRNAs与COI序列亚种间变异与亚种内变异之间有明显的条形码间隙,有利于区分亚种。【结论】tRNAs和COI序列可用于种及亚种的鉴定。

Comparison and Identification of DNA Sequences of Oysters in the Genus Crassostrea

【Objective】In order to understand the phylogenetic relationship and species distinction of oysters in the genus Crassostrea,finding fast and effective species identification methods by analyzing the sequence alignment of 7 gene fragments were used.【Method】Molecular phylogenetics to mitochondrial DNA and internal transcribed spacers of ribosomal RNA genes from Crassostrea hongkongensis,Crassostrea ariakensis,Crassostrea sikamea,Crassostrea nippona,Crassostrea iredalei,Crassostrea gigas gigas,and Crassostrea gigas angulata were investigated to differentiate the species.【Result】Comparison of the inter-and intra-sub-specific sequence divergence revealed that tRNAs presented the most divergent inter-subspecific variations and TS1 was the most divergent intra-subspecific variations.The tRNAs and COI represented the highest mutational rate and distinct barcoding gap,and could be used to differentiate the species.The 12S,16S,ITS,and ITS2 sequences did not overlap or present a barcoding gap.Similarly,the ITS1 sequences overlapped,but did not present a barcoding gap.Therefore,it could not be used to differentiate the species.In the subspecies,the tRNA and COI sequence variations presented distinct barcoding gaps,facilitating the differentiation of subspecies.None of the remaining sequences overlapped or presented barcoding gaps.【Conclusion】The mitochondrial tRNAs and COI could be used for species/subspecies identification.These findings reveal the phylogenetic relationships among the oysters and differentiate different oyster species,which could further guide the genetic improvement of oysters and promote corresponding resource management and protection.