Genetic Diversity Analysis For Hemifusus Tuba Gmelin By Microsatellite Molecular Screening And16S RRNA Gene Cloning

The Hemifusus tuba Gmelin, belongs to the family of Melongenidae, Gastropod, having a widedistribution on sandy and muddy substrata at depths up to20m along the coastal waters of Philippines,Southeast China and Japan. Owing to its delicious taste and nutritive value, H. tuba has been sold as luxuryfood items and became an important resource for coastal fisheries. However, overfishing and the damage ofnatural habitat have led to a sharp decline of natural resources in recent years. At present with theworsening environmental pollution of the water body and the different degrees of human subjectiveintervention control on Hemifusus tuba Gmelin groups, led to the inevitable result was its genetic diversitydecreased. Resulting the decreasing of ability to withstand environmental change, slow growing and otherphenomena. Using SSR molecular genetic markers and16S rRNA gene cloning on the Hemifusus tubaGmelin genetic diversity analysis, to achieve the purpose that to protect the germplasm resources and tokeep the sustainable development and utilization is very necessary.In this study, microsatellite DNA markers were developed from transcriptome sequences database andpolymorphism of each locus was assessed in a wild Hemifusus tuba Gmelin population. Number of allelesper locus ranged from three to ten. The observed and expected heterozygosities ranged from0.067to1.000and from0.097to0.897, respectively. The polymorphism information content (PIC) ranged from0.090to0.779. Five of the forty-two loci significantly deviated from the Hardy-Weinberg equilibrium afterBonferroni correction for multiple tests. Most of those loci are in Hardy-Weinberg equilibrium (P>0.05after Bonferroni correction).One hundred and fifty samples of five natural Hemifusus tuba Gmelin population along the coastalwaters of south and east China were taken to study the genetic diversity and genetic structure of thesepopulations (Qingdao, Xiangshan, Dongtou, Beihai, Sanya) by the method of microsatellite molecularscreening and16S rRNA gene cloning. A total of80alleles were detected by five pairs of SSR primers,with a mean of16bands per primer. In these five H. tube populations, the average number of allele (N)ranged from9to13; the average number of effective allele (Ne) were6.26to8.59; the value of averageobserved heterozygosity (Ho) in five populations were0.8588to0.8910; the value of average exceptedheterozygosity (He) were0.9222to0.9489; the value of average polymorphism information content (PIC)were0.8116to0.8714; the value of Shannon’s index (I) ranged from1.9175to2.3164. From this research,the five wild Hemifusus tuba Gmelin population were both abundant in genetic diversity and breedingpotential．Among the five H. tube populations，the polymorphism of the wild population from Qingdao wasthe highest (the value of N, Ne, Ho, He, PIC and I were8.5935,0.8910,0.9489,0.8714and2.3164), andthe polymorphism of samples from Beihai was lower (the value of N, Ne, Ho, He, PIC and I were6.2600,0.8588,0.9222,0.8116and1.9175) relatively.Based on sequencing results of16S rRNA cloning, the genetic distance of five H.tube populations wascalculated and cluster analysis was carried out using un-weighted pair group method arithmetic average(UPGMA). The results show that the populations of Qingdao and Xiangshan were similar, and Dongtou population has close genetic distance to them, they clustered into one group. While the populations ofBeihai and Sanya were similar, they clustered into another group. The mean fixation index (Fst) of five H.tube populations was0.0573, suggest medium degree of genetic differences between groups.