Location: Cool and Cold Water Aquaculture ResearchTitle: Mapping and expression of candidate genes for development rate in rainbow trout (Oncorhynchus mykiss)) Author
Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2014
Publication Date: 4/17/2014
Citation: Hale, M.C., Colletii, J., Gahr, S., Scardina, J., Thrower, F., Harmon, M., Carter, M., Phillips, R.B., Thorgaard, G., Rexroad III, C.E., Nichols, K. 2014. Mapping and expression of candidate genes for development rate in rainbow trout (Oncorhynchus mykiss). Journal of Heredity 2014:105(4):506–520 Interpretive Summary: Development rate is associated with a wide range of variables important to the lifecyles of salmonid fishes, including growth rate and age at sexual maturity. It was previously determined that a region on rainbow trout chromosome 5 affects traits associated with development rate. We placed 21 genes known to be involved in growth and development in other species on the trout genetic map. Genes that mapped to chromosome 5 were evaluated for their gene expression during embryonic development, suggesting that: 1) they could contain genetic variation that affects growth and development rates; and 2) they are targets for selection schemes aimed at improving aquaculture production efficiency.
Technical Abstract: Development rate has important implications for many aspects of an individual's biology. In rainbow trout (Oncorhynchus mykiss), a major QTL for embryonic development rate has been detected on chromosome 5, but at present, few candidate genes have been mapped to this region. This paucity of known genes and lack of a genome reference sequence for this species makes determining the genetic architecture of this trait difficult. We identified and mapped several candidate genes known to be involved in development, growth and metabolic pathways. In addition, we used quantitative PCR (qPCR) methods to characterize gene expression profiles of these genes throughout embryonic development. Most genes were up-regulated at the eyed stage of development. Although there is a link between development rate and the propensity for an individual to migrate, there were no expression differences between a population of anadromous steelhead trout and a population of resident rainbow trout. However, we found evidence of associations between cross type and two candidate genes (Clock1b and Myd118-1) associated with embryonic development; and that progeny from resident fish develop significantly faster than progeny from migratory fish. These results confirm a link between development rate and migratory strategies.