Genetics, Vol. 166, 1761-1773, April 2004, Copyright © 2004
The Evolution of the Drosophila Sex-Determination Pathway
Andrew Pomiankowskia,
Rolf Nöthigerb, and
Adam Wilkinsc
a Department of Biology, University College, London NW1 2HE, United Kingdom,
b Zoological Institute, University of Zürich, CH-8057 Zürich, Switzerland
c BioEssays, Cambridge CB1 1HN, United Kingdom
Corresponding author:
Andrew Pomiankowski, University College, 4 Stephenson Way, London NW1 2HE, United Kingdom., ucbhpom{at}ucl.ac.uk (E-mail)
Communicating editor: T. SCHÜPBACH
The molecular complexity of the Drosophila somatic sex-determination pathway poses formidable intellectual challenges for attempts to explain its evolutionary origins. Here we present a reconstruction of how this regulatory cascade might have evolved in a step-by-step fashion. We illustrate how mutations in genes, which were already part of the pathway or were recruited as new regulators of the pathway, were favored by sexual selection acting on the discriminatory sex-determining signal. This allows us to explain the major features of the pathway, including multiple promoter sites, alternative splicing patterns, autoregulation, and stop codons. Our hypothesis is built on the available data from Drosophila and other insect species, and we point out where it is amenable to further experimental and comparative tests.
