Genetic Structure And Differentiation Of The Selected Lines Of Pinctada Martensii, As Revealed By SSR Marker Systems

1. Genetic structure and genetic differentiation between the second generation yellow color shell and control lines of Pinctada martensii were analyzed using SSR marker systems. It was found that a total of 34 alleles were detected by 6 primers. All the loci were polymorphic and the number of alleles ranged from 4 to 7, with a mean of 6.667 alleles per locus. The average valid allele number in the two lines were 1.6433 and 1.8356, respectively; the average observed heterozygosity in the two linrs were 0.3854 and 0.4792, respectively; the average expected heterozygosity in the two lines were 0.3754 and 0.4429, respectively; the average PIC were 0.6660 and 0.7153, respectively. The results indicated that genetic diversity of the two lines was medium, and there existed moderate differentiation.2. Genetic structure and genetic differentiation among four yellow shell color families of Pinctada martensii were analyzed by SSR markers. It was found that a total of 32 alleles were detected by the 7 primers. All the loci were polymorphic and the number of alleles ranged from 2 to 8, with a mean of 4.571 alleles per locus. During the four families: the average effective numbers of alleles of the four families were from 1.8122 to 2.0896. The average expected heterozygosity and the average observed heterozygosity were 0.2757-0.3538 and 0.3400-0.3654, respectively. PIC values were between 0.5024-0.5670. Shannon's diversity was 0.7184-0.8103. These result indicated that genetic diversity of the four families were high. The average coefficient of genetic differentiation was 0.0627. Genetic distance ranged from 0.0306 to 0.1649 and genetic identity ranged from 0.8480 to 0.9699, implying that the four families have moderately genetic differentiated.