Fig. 4. Tissue distribution of mRNAs encoding (A) NKCC1a, (B) NKCC1b, (C) NKCC2, (D) NCC, (E) NHE3 and (F) vacuolar-type H⁺-ATPase A-subunit in Mozambique tilapia acclimatized to freshwater (FW) and seawater (SW), quantified using real-time PCR. The yolk-sac membrane of embryos 4 days after fertilization (YSM), adult gills, kidney, intestine and brain were examined. Each value represents the mean ± s.e.m., N=7 (YSM) and N=3 (adult tissues). The data were normalized to the highest-expressing tissue for each gene, which were assigned an arbitrary value of 1.