Gene expression profiling of soft and firm Atlantic salmon fillet

Microarray analyses revealed strong correlations between firmness of fillet (most important quality parameter) and a large number of genes. Highly similar expression profiles were observed in several functional groups. Positive regression was found between firmness and genes encoding proteasome components (41 genes) and mitochondrial proteins (129 genes), proteins involved in stress responses (12 genes) and lipid metabolism (30 genes). A weaker though highly significant negative regression was seen in sugar metabolism (26 genes) and myofiber proteins (42 genes). Among individual genes that showed a strong association with firmness, there were extracellular matrix proteins (negative correlation), immune genes and intracellular proteases (positive correlation). Several genes can be regarded as candidate markers of flesh quality (coiled-coil transcriptional coactivator b, AMP deaminase 3 and oligopeptide transporter 15) though their functional roles are unclear. Fillet firmness in a population of farmed Atlantic salmon with known pedigree. Sixteen individuals were chosen to cover the normal range of this trait.