Morphology of pelvic fin loss in a zebrafish strain (Danio rerio)

We describe the morphology of a zebrafish strain which lacks pelvic fins but no other abnormalities. This description is the first step of analyzing hindlimb loss in an established model organism. By combining light microscopy, bone and cartilage staining, scanning electron microscopy and histological sections we were able to comprehensively describe the morphology of the developing pelvic fins of a pelvic finless zebrafish in contrast with the developing pelvic fins of wild-type zebrafish. We have shown that although adult pelvic finless zebrafish completely lack pelvic fins, they do develop mesenchymal bulges in the pelvic regions at the pelvic fin development stage. Understanding the morphology and the subsequent genetic analysis of this fish will lead to important insights into both pelvic fin/hindlimb developmental mechanisms and the evolution of hindlimb loss. It is for this reason that we present a morphological analysis of pelvic fin development and loss in this genetically tractable model species.