Study Of EST-SSR On Polymorphism, Association Analysis With Growth Traits On Litopenaeus Vannamei

EST-SSR technology and DNA sequencing was applied to analyze the polymorphisms and the functional gene related to the growth traits of 360 cultured Litopenaeus vannamei from Hainan Province, aimed to evaluate the years select breeding, find the relevance between EST-SSR loci and growth traits and predict the functional genes. The results showed as follows:(1) 14 microsatellite DNA universal markers derived from Belgian wild shrimps expressed sequences tags (ESTs) were selected and evaluated. Stable banding pattern were shown by 8 EST-SSRs, and 5 of them (CNM-MG 345, CNM-MG 390, CNM-MG 437, CNM-MG 444, CNM-MG 487) were identified as the polymorphism EST-SSR, and can be used in the next study.(2) The 5 EST-SSR loci above-mentioned subsequently used for genotyping of 360 cultured adult white shrimps sampled from Hainan province. The characterization results, which revealed 12 alleles and 2.4000±0.5477 alleles per locus, observed and expected heterozygosis'levels ranged from 0.2792 to 0.8208 and from 0.3779 to 0.6011 respectively, showed the moderate polymorphisms at these loci.(3) The correlation analysis revealed that there were very significant effect of the CNM-MG 390 and CNM-MG 444 for body weight (BW) (P<0.01), significant effect of CNM-MG 390 for total length (TL), and CNM-MG 487 for carapace width (CW). Five major genotypes of shrimp growth traits were found. The body weight was contributed by the genotype of BB of CNM-MG 390 and AA, AC of CNM-MG 444, the carapace width was contributed by the genotype of AA of CNM-MG 487, while the total length was contributed by the genotype of AB of CNM-MG 390.(4) Three homologous protein were found by the blastx between eight EST-SSR sequences and protein database of GenBank. The iron regulatory protein 1 of Pacifastacus leniusculus, the polyadenylate-binding protein of Mus Musculus and 60 S acidic ribosomal protein P2 of Sus Scrofa showed a definite similarity with the sequences of CNM-MG 390, CNM-MG 444 and CNM-MG 529. However, the mechanism of these functional gene related to the shrimp growth and metabolism should be study for further.This study set the foundation for population genetics studies, selective breeding and growth quality improvement in Litopenaeus vannamei.