Abstract
Red coloration of muscle tissue (flesh) is a unique trait in several salmonid genera, including Atlantic salmon. The color results from dietary carotenoids deposited in the flesh, whereas the color intensity is affected both by diet and genetic components. Herein we report on a genome-wide association study (GWAS) to identify genetic variation underlying this trait. Two SNPs on ssa26 showed strong associations to the flesh color in salmon. Two genes known to be involved in carotenoid metabolism were located in this QTL- region: beta-carotene oxygenase 1 (bco1) and beta-carotene oxygenase 1 like (bco1l). To determine whether flesh color variation is caused by one, or both, of these genes, functional studies were carried out including mRNA and protein expression in fish with red and pale flesh color. The catalytic abilities of these two genes were also tested with different carotenoids. Our results suggest bco1l to be the most likely gene to explain the flesh color variation observed in this population.
Highlights
All salmon, trout and char species in the genera Salmo, Parahucho, Oncorhynchus, and Salvelinus, have a unique and characteristic red flesh color[1]
The highest scoring single-nucleotide polymorphisms (SNPs) in the genome-wide study was positioned in the region encompassing the two paralogous genes bco[1] and bco1l
Considering the already known role of BCO1 in carotenoid metabolism, the two paralogs arose as obvious candidate genes for salmon flesh color
Summary
Trout and char species in the genera Salmo, Parahucho, Oncorhynchus, and Salvelinus, have a unique and characteristic red flesh color[1]. BCO1 provide retinal (a form of vitamin A) through the oxidative cleavage of beta-carotene, a carotenoid which contain two beta-ionone rings. Carotenoids without any unsubstituted beta-ionone ring, such as astaxanthin and zeaxanthin, cannot be cleaved by BCO1 and are atypical vitamin A sources in mammals[12,13,18,19,20,21,22]. The strongest associated SNPs were located within and between two gene paralogs bco[1] and bco1l at chromosome 26. These two genes were functionally tested, including the quantification of mRNA and protein expression in red- and pale-fleshed fish. RNAseq was used to compare the gene expression profiles in intestinal tissue from red and pale fish, and to investigate the expression of the bco[1] splice variants
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
