Meeting Abstract

P1-11  Saturday, Jan. 4  Patterning and development of the beluga whale (Delphinapterus leucas) fluke GAVAZZI, LM*; COOPER, LN; THEWISSEN , JGM; Kent State University, Kent, OH and Northeast Ohio Medical University, Rootstown, OH; Northeast Ohio Medical University, Rootstown, OH; Northeast Ohio Medical University, Rootstown, OH lmgavazzi@gmail.com

Cetaceans, the order containing whales, dolphins, and porpoises, utilize a fluked tail as the main propulsive organ during locomotion. The fluke is the lateral soft tissue outgrowth at the caudal-most region of the vertebral column, and the emergence of this structure is evolutionarily correlated with the loss of hindlimbs. It is previously well-documented that the fluke embryonically originates as a diamond-shaped thickening on the tip of the tail. It expands mediolaterally to form a spade shape, before inverting into the final triangular, notched structure. While there have been several studies concerned with the morphogenesis of the cetacean fluke during embryonic development, the molecular underpinnings of this structure are unknown. Using fluke tissue from several fetal belugas, we performed immunohistochemistry and tested for the presence of sonic hedgehog (SHH) and FGF-10, two proteins that are critical during embryogenesis. Staining for SHH was found sporadically in the epithelium and some regions of connective tissue. FGF-10 staining in the epithelium was consistent, with stronger signal found in the lateral and ventral regions of the fluke.