Study On Genetic Diversity Of Meretrix Meretrix By Two Kinds Of Molecular Makers: RAPD And ISSR

Merelrix meretrix, Cyclimi sinesis and Mactra vecerifermis are important aquaculture shellfishes |n Jiangsu Province. The genetic polymorphisms of these shellfishes, collected from Lusi coastal, were studied by the randomly amplified polymorphic DNA technique. 60 random primers were used to test the 24 samples of three kinds of shellfishes. There are 45 primers were chosen for generating total 250 high steady hands. According to the Nei's formula, the genetic comparability Index was counted. A phylogenetic tree was constructed using UPGMA program based on the indexes of three species of shellfishes. The genetic distances between every two of three shellfishes (0.2785, 0.2739, 0.2805) was very close. The quantitative of Merelrix meretrix's germ plasm have been declining through studies of comparing genetic polymorphisms of these three shellfishes .Inter-Simple Sequence Repeates (ISSR) was applied to preliminary study on the genetic variation of two stocks of Merefix meretrix. 13 ISSR primers were selected from 100 primers offered by University of British Columbia. Each primer yeilded from 1 to 8 bands with the average of 4.6 bands . The results demonstrated that the genetic polymorphism of Jiangsu's (80.7%) was higher than Liaoning's( 68.4%). and it's average genetic distance of inter-stock 0.3105?.090 was bigger than Liaoning's 0.2658?.044 as well. The selective primers can declared that the simple sequence tandem repeats (STRs) of Meretrix meretrix were mainly composed of AG dinucleotede repeats. Through comparing the differnet reaction conditions, the ISSR-PCR reaction system was optimized.The study through preanalysised two kinds of molecular markers practised onMcretrix meretrix demonstrated that the genetic distance of Mcretrix meretrix was smaller than Cyclina sincsis and Mactra veccrifcrmis ; it's germ plasm was realitively degenerated; comparing Meretrix meretrix of Liaoning . Jiangsu's have larger genetic improving potential.