Molecular Cloning, Screening of Single Nucleotide Polymorphisms, and Analysis of Growth-Associated Traits of igf2 in Spotted Sea Bass (Lateolabrax maculatus)

SIMPLE SUMMARY: The spotted sea bass (Lateolabrax maculatus) is an economically important fish species cultured in China. Single nucleotide polymorphisms (SNPs) associated significantly with growth traits were screened to promote culturing conditions for L. maculatus. The insulin-like growth factor 2 gene (igf2) of L. maculatus was isolated. Fourteen SNPs were detected from the genome sequence of igf2. Four SNPs were associated significantly with the growth traits of L. maculatus. The SNPs we identified could be valuable for the genetic breeding of L. maculatus. ABSTRACT: The insulin-like growth factor 2 gene (igf2) is thought to be a key factor that could regulate animal growth. In fish, few researchers have reported on the single nucleotide polymorphisms (SNPs) located in igf2 and their association with growth traits. We screened the SNPs of igf2 from the spotted sea bass (Lateolabrax maculatus) by Sanger sequencing and made an association between these SNPs with growth traits. The full-length complementary (c) DNA of igf2 was 1045 bp, including an open reading frame of 648 bp. The amino acid sequence of Igf2 contained a signal peptide, an IGF domain, and an IGF2_C domain. Multiple sequence alignment showed that the IGF domain and IGF2_C domain were conserved in vertebrates. The genome sequence of igf2 had a length of 6227 bp. Fourteen SNPs (13 in the introns and one in one of the exons) were found in the genome sequence of igf2. Four SNPs located in the intron were significantly associated with growth traits (p < 0.05). These results demonstrated that these SNPs could be candidate molecular markers for breeding programs in L. maculatus.