Comparative Analysis of the Shared Sex-Determination Region (SDR) among Salmonid Fishes.
Bottom Line: This variation results from the movement of the sex-determining gene, sdY, throughout the salmonid genome.We found approximately 4.1 kb of orthologous sequence common to all three species, which contains the genetic content necessary for masculinization.The regions contain transposable elements that may be responsible for the translocations of the SDR throughout salmonid genomes and we examine potential mechanistic roles of each one.
Affiliation: Department of Biology, Portland State University School of Biological Sciences, Washington State University Vancouver.Show MeSH
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Mentions: Phylogenetic relationships show these two pol-like protein sequences do not have direct shared ancestry, therefore it is an unlikely candidate TE responsible for the relocation of the SDR cassette in all salmonid genomes (fig. 6). Additionally, the retrotransposons are found in opposite orientations in Atlantic salmon and rainbow trout. In Atlantic salmon, the pol-like protein has a plus/minus alignment relative to the SDR scaffold, but in rainbow trout the gene has a plus/plus orientation. All evidence suggests the two separate pol-like protein retrotransposons are coincidentally found in close proximity to the SDR in multiple salmonids. The position and orientation of the element in Atlantic salmon makes it a potential candidate for movement of the SDR via retrotransposon-mediated transduction (Xing et al. 2006), however this is not likely the mechanism in either Oncorhynchus species examined unless the signature following transduction was completely lost.Fig. 6.—
Affiliation: Department of Biology, Portland State University School of Biological Sciences, Washington State University Vancouver.