Restriction fragment length polymorphism of rDNA in the redfishes Sebastes fasciatus and S. mentella (Scorpaenidae) from the Gulf of St. Lawrence

• Published in: Canadian Journal of Zoology
• Main Authors: Desrosiers, B, Sévigny, J -M, Chanut, J -P
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1999
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Sebastes mentella
• Online Access: http://dx.doi.org/10.1139/z98-208; http://www.nrcresearchpress.com/doi/pdf/10.1139/z98-208

A restriction fragment length polymorphism (RFLP) analysis was carried out on nuclear ribosomal DNA (rDNA) of the redfishes Sebastes fasciatus and Sebastes mentella from the Gulf of St. Lawrence in an attempt to describe new molecular markers that would discriminate these two sibling species. The RFLP analysis revealed heterogeneity in the size of the repeat unit within and among individuals that is most likely the result of variation in the length of the intergenic spacer. Double digestion of rDNA with the restriction enzymes EcoRI and ScaI and subsequent hybridization with a 28S probe revealed the presence of three patterns of fragments. Two fragment groups seem to characterize S. mentella and S. fasciatus. Both fragment groups were present in several specimens, suggesting either a restriction-site polymorphism in S. mentella or a hybrid origin for these redfish. Discriminant analysis clearly differentiated all three rDNA patterns. Comparisons of genetic variations at the MDH* locus and of the number of soft rays in the anal fin among the three rDNA-defined groups suggest that if the individuals showing the two groups of fragments are hybrids between S. fasciatus and S. mentella, introgression has also occurred in the Gulf of St. Lawrence.