Abstract

The morphological and functional evolution of appendages has played a crucial role in the adaptive radiation of tetrapods, arthropods and winged insects. The origin and diversification of fins, wings and other structures, long a focus of palaeontology, can now be approached through developmental genetics. Modifications of appendage number and architecture in each phylum are correlated with regulatory changes in specific patterning genes. Although their respective evolutionary histories are unique, vertebrate, insect and other animal appendages are organized by a similar genetic regulatory system that may have been established in a common ancestor.

1. Neil Shubin is in the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
2. Cliff Tabin is in the Department of Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
3. Sean Carroll is at the HHMI and Laboratory of Molecular Biology, University of Wisconsin, 1525 Linden Drive, Madison, Wisconsin 53706, USA

Correspondence to: Neil Shubin Correspondence and requests for materials should be addressed to N.S. (e-mail: Email: nshubin@sas.upenn.edu).