Study On Molecular Markers Of Some Pearl Oysters In Pinctada And Genetic Mapping Of P.fucata (Gould)

Pearl oysters in Pinctada include some economically important species. Yet the taxonomic status of some pearl oysters is problematic. Their molecular markers are poorly reported as well. In the present study, (1) P. maxima,P. margarilifera, P. nigra,P. albina, P. chemnitzi, P. fucata as well as Pteria penguin were studied using RAPD markers in order to develop interspecific marker for species identification; (2) inheritance of AFLP markers in families of Pinctada fucata were investigated using AFLP markers, based on which a draft genetic map was constructed. The aim of this study is to provide basis for molecular marker-assisted selection in genetic breeding of pearl oysters.Random amplified polymorphic DNA (RAPD) analysis on the seven species was conducted using four primers (S10, S17, S358 and 0PM17) screened from 21 primers of S and OPM series oligo-nucleotide. The four primers produced 57 loci. The average number of loci amplified by each primer was 14.3. The mean number of bands per species amplified by each primer was 4.9 with length varying from 250 bp to 2000 bp. Primer S10 generated diagnostic markers that can distinguish the seven species simultaneously. The other three primers could discriminate two or more species from the others. It suggests that these four primers can be used in combination as molecular markers for species identification.Amplified fragment length polymorphism (AFLP) technique was used to investigate the genetic variation of the three families(PII, Indian ♀ ×Indian♂; PSI, Sanya ♀×Indian♂; PSS, Sanya♀×Sanya♂). The three primer pairs generated 57 loci among which 93.0— 100.0% is polymorphic. An overall genetic diversity was 0.4653 among populations and an average of 0.3997 ± 0.0173 within populations.Genetic diversity within populations (PII, PSI, PSS) was 0.4101, 0.4230, 0.3660, respectively, showing that the genetic diversity of progeny between parents from different geographical populations was higher than that from the same geographical populations. Genetic differentiation among the three populations was high (0.1410). The results indicated that interpopulation and intrapopulation were high genetic variance, the maximum of genetic distances was between PII and PSS (0.1828), the minimum was between PII and PSI (0.1327). All individuals from the same family clustered into a single group as demonstrated by minimum evolution (ME) tree. Among the three families, PII and PSI were closely distant and grouped together.