Identification of growth-related genes based on BSA in Pacific white shrimp Litopenaeus vannamei

The development of SNP genotyping techniques has facilitated the application of genome-wide association studies (GWAS) and genomic selection (GS) in plants and animals. However, the cost of high-throughput SNP genotyping is particularly high in the case of aquaculture animals which can produce a large number of offspring. Consequently, a cost effective method for trait-associated SNP identification and application was urgently needed in aquaculture breeding. In this study, a Bulk Segregation Analysis sequencing (BSA-seq) method was employed to identify growth-related single nucleotide polymorphisms (SNPs) and genes in the Pacific white shrimp Litopenaeus vannamei. Two independent families were used for this analysis to reduce the false positive. The DNA of individuals with the highest and lowest body weights was pooled separately. Two methods including the ED (Euclidean distance) method and the chi-square test were applied to calculate the allele differences between high and low growth rate individuals. A total of 24,325,437 SNPs were identified and consequently 1,299 SNPs and 163 genes were identified to be associated with growth traits. KEGG enrichment analysis showed that these genes were significantly enriched in phosphatidylinositol signaling system and phospholipase D signaling pathway. The diacylglycerol kinase genes, phosphatidylinositol 3-kinase genes, inositol polyphosphate 5-phosphatase genes, mitogen-activated protein kinase genes, myotubularin-related protein genes and epidermal growth factor receptor genes in these pathways were considered as candidate growth genes. This study demonstrated that the BSA-seq based on whole genome resequencing is cost-effective and useful in aquaculture. The results not only provide useful information for understanding the genetic basis of growth traits, but also offer a source of SNPs for marker-assisted selection (MAS) and genomic selection (GS) in shrimp.