Sequence analysis of the growth hormone gene of the South American catfish Rhamdia quelen.

Rhamdia quelen is an important Neotropical catfish species for fisheries and aquaculture in southern Brazil, where it is called Jandia. Like other native Brazilian species of economic importance, R. quelen genetics needs more attention for animal breeding programs. The growth hormone gene is known to be linked to a number of molecular markers and quantitative trait loci. We sequenced the coding region of the growth hormone gene with the primer walking technique. As in other Siluriformes, the R. quelen growth hormone gene has four introns and five exons, in a 1465-bp coding region. The tertiary structure of the encoded protein was predicted by bioinformatics; it has four α-helix structures connected by loops, which form a compressed complex maintained by two disulfide bridges.