Genetic Diversity Of Calanoid Copepods Euchaeta Concinna And Calanus Sinicus In Nearshore Waters Of China Seas

Copepoda are an important part of marine zooplankton. Due to the differences in the geographic environments and the ecological conditions among different geographic sea areas in China,the community structures and characters of zooplankton in different sea areas are various.Genetic differentiation in some species in common may occur during the courses of adapting to different environments, natural selection and genetic drift.In this study,we try to estimate the genetic diversity of Calanus sinicus in several sea areas by using MtDNA gene fragment sequence analysis。And we also estimate the genetic diversity of Euchaeta concinna in East China Sea by using Inter-simple sequence repeat (ISSR).DNA sequence analysis is very useful for the genetic diversity analysis at molecular level. Rapid evolution and unrecombination are characteristic of mtDNA sequence and these make it a strong tool to estimate genetic differentiation. In this study we amplify the mtCOI gene fragments of Calanus sinicus collected from Bohai Sea, Yellow Sea,East China Sea, South China Sea. By analysising the sequence of mtCOI gene fragments(including other sequences in our lab of Calanus sinicus collected from four sea areas above and Qingdao adjacent waters), the genetic diversity and genetic differentiation were studied. DNA sequence variation for a 589 base-pair region of mt16S mtCOI resolved 39 different haplotypes and 48 polymorphic sites among the 239 individuals. The base composing was 23.5%,19.6%,22.7% and 34.2% for the average contents of A, C, G, T. Mean genetic distance analysis indicates that the genetic differentiation of the seven populations was at a low level while distance value between East china Sea and other areas are particular higher than others.ISSR were used to estimate genetic diversity and relationship in DNA of Euchaeta concinna in there sites of East China Sea.7 primers were selected. The result demonstrates that the three populations have high level of similarity but low level of differentiation. The extent of differentiation between 1004 and 609(which is far from each other in geography)is much greater, suggesting hereditary differentiation may exit between E.concinna populations in East China Sea.