Oh, those crazy geneticists! Who thinks of naming a gene “Hedgehog”, anyway? The name may be frivolous, but the Hedgehog Signaling Pathway is certainly not, as it is required during the embryogenesis of many organisms. The Hedgehog Signaling Pathway Database, through the San Francisco State University, provides a number of online tools for researchers studying this pathway. There are diagrams of Hedgehog signal transduction (though not the most polished diagrams I’ve ever seen), a list of genes involved in Hedgehog signaling, and a list of Hedgehog-related diseases and human mutations (along with links to relevant clinical trials). Additionally, the “Stem Cells” tab provides links to scientific papers related to stem cells and the Hedgehog pathway. Sadly, the “Hedgehog Expression in Tissues” page is still under construction, so I would continue to check back as this site continues to develop.