Abstract:Genotype segregation of parents livestocks (G0 generation)and their offspring (G1 generation)of 6 Litopenaeus vannamei families was analyzed on basis of 7 microsatellite DNA markers.In addition, heterogeneity analysis for pairwise comparisons of expected heterozygosities (He) of all loci between G0 and G1 was carried out and genetic differentiation through F-statistics at each locus in G1 population was expected to monitor genetic variation in Litopenaeus vannamei breeding. The results showed that 44 alleles were detected in total across 7 loci assayed,mean number per locus,mean expected heterozygosity and mean polymorphism information content of G0 generation were 6.14, 0.786 and 0.709 respectively, and those of G1 generation were 6.27, 0.733 and 0.695 respectively. The combined exclusion probability of 7 microsatellite markers arrived at 0.99 and could seperate all 6 families with known parent. Heterogeneity analysis for pairwise comparisons of expected He of all loci between G0 and G1 indicated that He of G0 was significantly higher than G1(P<0.01). FST of G1 per locus ranged from 0.270 3 to 0.465 4 and average was 0.358 4 which meant that genetic differentiation in its subpopulation was high. The UPGMA analysis based on six families genetic distances showed all individuals of G1 generation could be classified into 4 categories.Similarly to families C and D, families A and B sharing father had high similarity coefficient and clustered together, family E and F were assigned into another group respectively.