1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA
2. Centre de Biologie du Développement, Bâtiment 4R3, 118 Route de Narbonne, 31062 cedex4 Toulouse, France
3. Vanguard High School, 317 East 67th Street, New York, New York 10021, USA
4. These authors contributed equally to this work
5. Present address: Instituto Gulbenkian de Ciência, Rua da quinta grande 6, 2780-156 Oeiras, Portugal

Correspondence to: David L. Stern¹ Email: dstern@princeton.edu
The NCBI accession numbers for svb/ovo fragments from D. virilis and D. borealis are AY184285 and AY184286, respectively.

Abstract

Cases of convergent evolution that involve changes in the same developmental pathway, called parallelism, provide evidence that a limited number of developmental changes are available to evolve a particular phenotype¹. To our knowledge, in no case are the genetic changes underlying morphological convergence understood. However, morphological convergence is not generally assumed to imply developmental parallelism². Here we investigate a case of convergence of larval morphology in insects and show that the loss of particular trichomes, observed in one species of the Drosophila melanogaster species group, has independently evolved multiple times in the distantly related D. virilis species group³. We present genetic and gene expression data showing that regulatory changes of the shavenbaby/ovo (svb/ovo) gene underlie all independent cases of this morphological convergence. Our results indicate that some developmental regulators might preferentially accumulate evolutionary changes and that morphological parallelism might therefore be more common than previously appreciated.