Meeting Abstract

45.3  Saturday, Jan. 5  The Role of Apoptosis in the Limbs of Urodeles and Anurans and in the Fins of Fish FRANSSEN, RA*; SHUBIN, NH; University of Chicago; University of Chicago franssen@uchicago.edu

Our previous work revealed that the direct-developing salamander Desmognathus aeneus utilizes cell death during normal limb development, raising the possibility that apoptosis is used as a tool for creating free digits in other species of salamanders, frogs, or even fish. In this study, we use TUNEL staining to determine if other amphibian or fish species also form limbs and digits using cell death. Included in our investigation are stream-dwelling and direct-developing urodeles, larval and direct-developing anurans, and basal actinopterygian and chondrichthyan fishes. Our results are consistent with previous findings that fishes and larval amphibians do not utilize cell death to pattern fins/limbs and digits/rays. However, we discovered apoptosis in the developing limbs and digits of rapidly developing amphibians, including stream-dwelling salamanders, direct-developing urodeles, and anurans. These findings suggest that the use of cell death to sculpt developing digits has evolved multiple times in the tetrapod lineage, and that the evolution of developmental mechanisms involving apoptosis is correlated to rate of development.