Primary Study On Mitochondrial DNA Of Scallop Chlamys Farreri

Chlamys farreri, belongs to Mollusca-Bivalvia-Pterioida-Pectinidae-Chlamys, is one of the most important cultured scallops in the north of China, which distributes mainly in Liaoning province and Shandong peninsula. Sucrose-mediated Differential Centrifugation DNase Method, Alkaline Denaturalization Method and Triton Method were used to extract mitochondrial DN A from the muscle tissue and gonad tissue of C. farreri. Through agarose-gel electrophoresis and FIGE, mtDNA was detected and reveals the molecular size ranging from 25kb to 35kb. Such differentia remains among individuals. A protocol for scallop mtDNA isolation is finally proposed based on the compariation of these three methods.16S rRNA gene fragments are amplified by PCR respectively from Chlamys farreri and Chlamys nobilis. Comparing these two sequences, we designed three pairs of selective primers for the identification of these two scallops. A 310 bp fragment can be amplified within the 16S rRNA gene from C. nobilis by primer pair HG2/SB, while a 347 bp fragment and a 634 bp fragment can be amplified from C. farreri by primer pair ZK2/SB and SAGG/SBAA respectively. This method is easy and convenient to distinguish C. farreri from C. nobilis or vice versa. As applied to their hybrids, both cross and backcross filial generation show the same PCR products as their female parent, indicating the maternal inheritance is the only or the predominant pattern of inheritance of mitochondrial DNAin scallop.CO I gene fragment are also amplified from Chlamys farreri with the length of 718bp. Restriction enzymes BamHI HaeIII Mbo I Mse I Rsa I Pst I are used to detect the restrictive fragment length polymorphism, however only two site were detected, one by HaeIII, the other by TaqI. Finally, DHPLC analysis is used to verifythe mutation at the polymorphism site. The DHPLC result consistent with the RFLP result. This method is also used to check the heteroplasmy in the scallop's muscle and gonad tissue, while there is no evidence of DUl inheritance as was found in mussel.