Domestication and growth hormone transgenesis cause similar changes in gene expression profiles in coho salmon

By directly comparing gene expression in wild type, domestic, and GH transgenic strains of salmon, we have found that domestication and GH transgenesis are modifying similar genetic pathways. Genes in many different physiological pathways show modified expression in domestic and GH transgenic strains relative to wild-type, but effects are strongly correlated. Genes specifically involved in growth regulation (IGF-I, GHR, IGF-II, THR) are also concordantly regulated in domestic and transgenic fish, and both strains show elevated levels of circulating IGF-I. Muscle expression of GH in nontransgenic strains was found to be elevated in domesticated fish relative to wild type, providing a possible mechanism for growth enhancement. These data have implications for genetic improvement of existing domesticated species as well as regulation of emerging transgenic strains. Keywords: Expression profiling by array Microarray analyses were performed on four or five individual fish per group of wild type, domesticated, and GH transgenic salmon hybridized (one slide per individual) against a common wild-type RNA pool.