Study On The Genetic Diversity Of Solen Grandis Populations

Solen grandis, an important economic shellfish, distribute along the coast of intertidalzone. Amplified fragment length polymorphism(AFLP) and microsatellite markers were usedto estimate population genetics of Solen grandis. The results of this study could provideinformation to the breed of the new species. The main results of this research are as following:1. The AFLP system for Solen grandis was optimized including the time for DNA doubleenzymes digestion reaction, the dilute multiple for the per-amplification production anddifferent proportion in selective primers M+3/E+3. Then we selected seven primers to beused to the analysis of AFLP.141natural individuals from5populations of Solen grandiswere investigated using7primers. A total of403reproducible AFLP fragments, whichvaried most from100bp to700bp, were amplified among five populations,57.5fragmentsin every population averagely.2. The genetic structure and genetic diversity for five geographical populations of Solengrandis shows: there’s little different from DD, YT, LZ, NT, The percentage loci ofpopulation from RZ are relatively higher the other four, was79.16%, YT got the lowestnumber was69.23%. But, both the Shannon’s index and Nei’s index showed that the orderof genetic diversity level was as follows: RZ were higher than others, and the lowest wasNT.3. Comparing the genetic similarity coefficient and the genetic distance of5populationsfrom DD, YT, LZ, RZ and NT, the results showed that the genetic distance between DDand NT was the largest of0.091, and YT and RZ was the smallest of0.0205. The resultsindicated that, in the five natural populations, the relationship between RZ and YT wascloser, and the relationship between DD and NT was farther.4. The results of Analysis of Molecular Variation (AMOVA) revealed that the diversity ofSolen grandis was divided into two parts,22.5%from inter-population and77.5%fromintra-population. Significant test showed that the genetic differentiation of Solen grandispopulation (Φst=0.225, P <0.001) within and among groups were significantly. So theresults indicated that the genetic variation within populations was the important factorreflecting on genetic differentiation.5. Genetic diversity of Solen grandis populations was conducted using microsatellite DNA techniques.21alleles reproducible bands amplified with5primer combinations wereobtained from three populations and3-5were detected from each microsatellite locus.Average observed heterozygosity (Ho) of five populations was0.2769to0.4267, and theaverage value of polymorphism information content was0.3592to0.3958, respectively.6. Hardy-Weinberg equilibrium chi-square test and F-test data showed that the geneticstructure of the populations had been changed, including decreased heterozygous sites,increased loci deviated from the equilibrium, and decreased coefficient of geneticdifferentiation between five populations. Fst value (0.0751) suggested the Solen grandishad relatively weak genetic differentiation and illustrated that the main genetic variationexisted among individuals within population rather than between populations.