Identification of seven Crassostrea oysters from the South China Sea using PCR-RFLP analysis

• Published in: Journal of Molluscan Studies
• Main Authors: Xia, Jianjun, Yu, Ziniu, Kong, Xiaoyu
• Format: Text
• Language: English
• Published: Oxford University Press 2009
• Subjects: Research Papers; Crassostrea gigas
• Online Access: http://mollus.oxfordjournals.org/cgi/content/short/75/2/139; https://doi.org/10.1093/mollus/eyp001

We have developed a PCR–RFLP assay of two mitochondrial [16S rDNA and cytochrome oxidase I (COI)] and one nuclear (ITS-1) gene fragment for the identification of seven Crassostrea oysters from the South China Sea. These include the morphologically distinct Crassostrea sikamea and three pairs of morphologically similar species: Crassostrea hongkongensis and Crassostrea ariakensis , Crassostrea gigas and Crassostrea angulata , Crassostrea iredalei and an unidentified Crassostrea sp. All seven species can be distinguished with both mitochondrial markers: Dde I/ Dra I or Alu I/ Mse I digestion of 16S rDNA and Nis I/ Alu I or Nis I/ Dde I digestion of COI. Five of the seven species can be distinguished using a single endonuclease digestion of the ITS-1 fragment. Based on genetic distance estimates and on morphology, the newly discovered Crassostrea sp. appears most closely related to C. iredalei. Despite the existence of intra-specific variation at low frequency in some restriction sites, the PCR–RFLP assay developed here can be reliably applied to identify all seven oyster species.