Invertebrate and vertebrate patched genes are provided, including the
mouse and human patched genes, as well as methods for isolation of related genes,
where the genes may be of different species or in the same family. Having the ability
to regulate the expression of the patched gene, allows for the elucidation of embryonic
development, cellular regulation associated with signal transduction by the patched
gene, the identification of agonist and antagonist to signal transduction, identification
of ligands for binding to patched, isolation of the ligands, and assaying for levels
of transcription and expression of the patched gene.