Project description:This SuperSeries is composed of the SubSeries listed below. Growth in fishes is a complex trait, controlled by both genetic and environmental factors, that impacts many components of fitness. Gene expression studies may lead to the identification of candidate genes for growth and microarrays offer the opportunity to examine the expression of thousands of genes simultaneously. Gene expression differences in the liver and white muscle were examined in normally growing, 15 month-old, large and small size-selected rainbow trout (Oncorhynchus mykiss) derived from two different seasonal spawning groups (Sept. and Dec.). Examination of the gene expression differences in both liver and white muscle tissue allowed us to assess the seasonal influences upon gene expression patterns that occur in this species, and facilitated the identification of genes that may possess similar expression patterns regardless of seasonal effects. The analysis of global gene expression in large and small fish reared under standard conditions provides an understanding of typical growth patterns that may be observed in this species. The identification of candidate genes by this study may provide insight into the mechanisms of growth in fishes and may help to identify candidate genes for growth.
Project description:Diverse animals use Earth's magnetic field in orientation and navigation, but little is known about the molecular mechanisms that underlie magnetoreception. Recent studies have focused on two possibilities: (i) magnetite-based receptors; and (ii) biochemical reactions involving radical pairs. We used RNA sequencing to examine gene expression in the brain of rainbow trout (Oncorhynchus mykiss) after exposure to a magnetic pulse known to disrupt magnetic orientation behaviour. We identified 181 differentially expressed genes, including increased expression of six copies of the frim gene, which encodes a subunit of the universal iron-binding and trafficking protein ferritin. Functions linked to the oxidative effects of free iron (e.g. oxidoreductase activity, transition metal ion binding, mitochondrial oxidative phosphorylation) were also affected. These results are consistent with the hypothesis that a magnetic pulse alters or damages magnetite-based receptors and/or other iron-containing structures, which are subsequently repaired or replaced through processes involving ferritin. Additionally, some genes that function in the development and repair of photoreceptive structures (e.g. crggm3, purp, prl, gcip, crabp1 and pax6) were also differentially expressed, raising the possibility that a magnetic pulse might affect structures and processes unrelated to magnetite-based magnetoreceptors.