We present gene prioritization system (GPSy), a cross-species gene 
prioritization system that facilitates the arduous but critical task of 
prioritizing genes for follow-up functional analyses. GPSy's modular design with 
regard to species, data sets and scoring strategies enables users to formulate 
queries in a highly flexible manner. Currently, the system encompasses 20 topics 
related to conserved biological processes including male gamete development 
discussed in this article. The web server-based tool is freely available at 
http://gpsy.genouest.org.