Molecular characterization of slc5a6a and its association with growth and body conformation in bighead carp (Hypophthalmichthys nobilis)

Abstract

The slc5a6 (solute carrier family 5 member 6) gene is associated with the transport of several water-soluble vitamins and plays an important role in growth and development. Meanwhile, slc5a6a was localized in a genome-wide association analysis of head size and shape in bighead carp. In this study, characterization of slc5a6a were performed in bighead carp (Hypophthalmichthys nobilis), an important food fish in Asia. The full-length sequence of slc5a6a gene is 21,355 bp, with a cDNA of 5483 bp and open reading frame encoding 625 amino acids. Sequence comparison and phylogenetic analysis indicate that SLC5A6A is relatively conserved across vertebrates. Slc5a6a of bighead carp (Hynslc5a6a) is expressed in unfertilized eggs and embryonic stages like a maternal gene, with the highest expression in liver, followed by pituitary and muscle. In the expression of liver and pituitary of fast growing (Heavy group, HG) and slow growing (Light group, LG) individuals, HG is significantly higher than LG (P < 0.05). Three single nucleotide polymorphisms (g 0.5998 T > C, g.6104 A>G, g 0.21131 T > C) were identified in Hynslc5a6a and significantly associated with body weight (BW), body length (BL) and head length (HL). In one of the bighead carp populations, a combined triplotype CCGGCC of Hynslc5a6a was significantly better than TTAATC in the phenotype values of BW, HL and head width traits by 33.03 %, 12.26 % and 11.59 %, respectively. These results suggest that Hynslc5a6a plays an important regulation role in the growth and body conformation and dominant genotypes of this key gene are potentially applicable in marker-assisted selection in bighead carp.