Institution: | (1) Department of Aquaculture, Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden;(2) Institute of Zoology and Hydrobiology, University of Tartu, 46 Vanemuise Street, 51014 Tartu, Estonia;(3) Department of Fish Farming, Institute of Animal Science, Estonian Agricultural University, 1 Kreutzwaldi Street, 51014 Tartu, Estonia;(4) Finnish Game and Fisheries Research Institute, 6 FIN-00721 Helsinki, Finland;(5) Department of Animal Science, Helsinki University, 28FIN-00014, Helsinki, Finland |
Abstract: | Patterns of genetic diversity and differentiation among five wild and four hatchery populations of Atlantic salmon in the Baltic Sea were assessed based on eight assumedly neutral microsatellite loci and six gene-associated markers, including four expressed sequence tag (EST) linked and two major histocompatibility complex (MHC) linked tandem repeat markers (micro- and mini-satellites). The coalescent simulations based on the method of Beaumont and Nichols (1996, Proc. R. Soc. Lond. Ser. B – Biol. Sci., 263, 1619–1626) indicated that two loci (MHCIIα and Ssa171, with the lowest and highest overall FST estimates, respectively) exhibited significant departures (P<0.05) from the neutral expectations. Another coalescent-based test for selective neutrality (Vitalis et al. 2001, Genetics, 158, 1811–1823) further supported the outlier status of the Ssa171 microsatellite locus but not of the MHCIIα linked minisatellite. In addition, actin related protein linked microsatellite locus was identified with this test as an outlier in six pairwise population comparisons. All genetic diversity estimates revealed more genetic variation in hatchery stocks than in the small wild salmon populations from the Gulf of Finland. However, the wild populations possessed alleles at gene-associated markers (e.g. MHCI and IGF) not found in the hatchery stocks, which together with moderate genetic differentiation and distinctive environmental conditions justifies the special conservation measures for the last remaining native salmon populations in the Gulf of Finland. |