Figure 1.
Study area and experimental design.
a) Map of Norway showing the position of the sampling sites b) Locations of the two sampling sites, Glitredammen (freshwater) and Sandspollen (marine) c) Wild caught fish from both sampling locations were taken into the lab and placed in holding tanks of their native salinity for a minimum of three weeks. After acclimation, two groups of eight fish from both populations were exposed to either saltwater (30 PSU) or freshwater (0 PSU). The exposure tanks were divided in two by a perforated wall, so that both populations could be exposed to the same water quality at the same time d) Exposure times before the fish was collected and gill tissue was sampled.
Table 1.
Primers used for qPCR expression analysis of threespine stickleback genes.
Figure 2.
Relative mRNA-expression for the four targeted genes, ATP1A3, CFTR, KCNH4 and HSP70 in saltwater control (SS, dark orange), saltwater fish exposed to freshwater (SF, light orange), freshwater control (FF, dark blue) and freshwater fish exposed to saltwater (FS, light blue) for exposure periods relative to the 5 minute exposure.
Values between 0–1 indicate lower expression, and values over 1 indicate higher expression relative to the expression at 5 minutes.
Table 2.
Gene expression of four osmoregulatory genes (see Table 1) (Cq-values; mean ± se) for marine and freshwater stickleback after 5 min exposure to either salt or freshwater.