I found it interesting that many believers criticized the "God Gene" hypothesis on the basis that it reduced their link to trancendent reality to mere biochemistry. I personally feel it makes more sense, and that I'm probably one of many who aren't producing the "God Proteins" in sufficient quantities for belief.
I'm sure Mammuthus and Loudmouth would be able to comment on the genetics (or lack thereof) in the concept, but I doubt there is just one gene responsible for predisposition to religious belief. After all, most traits are the product of a complex of genes, and the religious issue would seem to have a lot of relevant factors.
regards,
Esteban Hambre