Increased diameter of arteries and veins in the caudal fins of Danio rerio longfint2 fish is accompanied by fin overgrowth

The classic dominant <i>longfin</i> zebrafish strain ( <i>lof ^t2</i> ) has long fins due to ectopic expression of the potassium channel Kcnh2a in the fin mesenchyme. Potassium channel function is also known to affect the vasculature, but the fin vasculature has not been characterized in <i>lof ^t2 </i> fish. Here we show that <i>lof ^t2 </i> fish contain significantly increased artery and vein diameters in the caudal fin as compared to wildtype fish. Interestingly, these changes in blood vessel size are associated with areas of fin overgrowth, consistent with a possible role for the vasculature in fin size regulation.&nbsp.