Abstract:Two distinct forms of zebrafish hepatocyte nuclear factor 1 (hnf1) were identified and referred to as hnf1α/tcf1 and hnf1β/tcf2. Both hnf1 genes were shown to be expressed abundantly in liver, pancreas, gut and kidney. Zebrafish HNF1α and HNF1β proteins contain all HNF1 signature domains including the dimerization domain, POU-like domain and atypical homeodomain. Sequence and phylogenetic analysis reveals that zebrafish hnf1α is closer to tetrapodian hnf1α than to tetrapodian hnf1β and zebrafish hnf1β is highly conserved with tetrapodian hnf1β. Existences of hnf1α and hnf1β in teleost zebrafish, tilapia and fugu suggest that hnf1 gene duplication might occur before the divergence of teleost and tetrapod ancestors. Zebrafish hnf1α and hnf1β genes were mapped to linkage group LG8 and LG15 in T51 panel by RH mapping and are composed of 10 and 9 exons, respectively. Zebrafish hnf1β gene with at least 11 genes in LG15 was identified to maintain the conserved synteny with those of human in chromosome 17 and those of mouse in chromosome 11. Our results indicate that distinct hnf1α and hnf1β genes in teleosts had been evolved from the hnf1 ancestor gene of chordate.