Fig. 2

Expression of HoxA11, HoxA13 and Wnt3 in little skate pectoral and pelvic fins. HoxA11 expression is located in the anterior pelvic fin, where the crura will elongate (a, b). In the pectoral fins, HoxA13 is expressed along the distal portion of the pectoral fin, with expression restricted at the distal mid fin (c). By stage 30, HoxA13 is restricted to the anterior most portion of the pectoral fin (d). Wnt3 is broadly expressed in the entire distal domains of the pectoral and pelvic fin at stage 29 of development, but then recedes to the anterior domains of the pectoral fin and the anterior and posterior domain in the pelvic fin (e, f). Note that HoxA11 expression overlaps with Wnt3 in the anterior pelvic fins (a, b, e, f) and HoxA13 expression in the pectoral fins overlaps with the anterior Wnt3 expression (d, f), indicating that HoxA11 and HoxA13 are associated with regions of outgrowth and novel AERs. Wnt3 images are courtesy of Nakamura et al. [20]. Black arrows mark expression