Bay Scallop Molecular Markers For The Study And Application

by Sun, Bo (Major: Marine Biology)Directed by Professor Zhang, Guofan and Dr. Liu, XiaoPopulation genetics of four Argopecten irradians cultured populations was analyzed by using Random Amplification Polymorphism DNA (RAPD) techniques. And partial DNA sequences of the Internal Transcribed Spacers(ITS) from four representative samples(one sample represent for each population) were amplified by PCR and sequenced in order to stress the phylogenetic relationships of the four populations. Besides, by RAPD technique, two Argopecten irradians families were studied to examine whether the hybridization experiments were successful and which family was more suitable to be materials in future genetic linkage map construction. The main results are shown as below: 1. 80 individuals from 4 populations (20 from each population) of Argopecten irradians were analyzed by using 20 random RAPD primers. 132 RAPD bands ranging from 230 to 2800bp were recorded with an average of 6.6 bands gained by per primer. The mean percentages of polymorphic loci of four populations were 31.82%(Zhejiang Population), 29.55%(Canada Population), 31.82%(Mexico Bay Scallop Population) and 28.79%(American F2 Population) respectively. The average heterozygosity (H) of them were 0.1078, 0.1134, 0.1197 and 0.0966 respectively. As for the genetic distances, Zhejiang Population is closer to Canada Population and their genetic distance is 0.0319; Mexico Bay Scallop Population and American F2 Population are closer and their genetic distance is 0.0368. Gst among the four populations is 0.1892, which means that 18.92% genetic variation of the whole population comes from the genetic differences among the four populations. 2. A 350bp fragment of ITS was gained and sequenced. Compared with the 5.8S complete sequence of the snail Arion rufus, ITS1 and ITS2 regions were recognized and combined for analysis. From sequence observation, it showed that the Zhejiang sample has more inserted sites and fragments while the sequences of other three are nearly all the same. The average G%+C% of the four individuals was 46.8% while the Zhejiang sample's was 48.3% and the other three's were all about 46.2%; Ts/Tv and genetic distance mainly lies between the Zhejiang sample and the other three individuals, which were 0.8 and 0.07 respectively. With the selected outgroup-Chlamys farreri, the phylogenetic trees suggested that Zhejiang Population has differentiated. 3. In Pb-Pa and Y1-P0 families of Argopecten irradians, 12 and 10 RAPD primers were selected, whichcould generate polymorphic bands in parents. In Pb-Pa, 37(30.3%) bands among the 122 bands recorded were polymorphic in parents. And by X2 test (P>0.05), 26 bands were 1:1 segregated, with 16 maternal and 10 fraternal. In Y1-P0, 32(33.7%) bands among the 95 bands recorded were polymorphic in parents. By X2 test, 22 bands were 1:1 segregated with 10 maternal and 12 fraternal. Judging from combination of all the markers, we conclude that hybridization were near full succeeded in the two families and the Y1-P0 family would be more potential in genetic linkage map construction.