It seems that Dean Hamer has one-upped Richard Dawkins on the god-meme with an argument for a god-gene in his book The God Gene: How Faith is Hardwired Into Our Genes.
“‘We think that all human beings have an innate capacity for spirituality and that that desire to reach out beyond oneself, which is at the heart of spirituality, is part of the human makeup,’ Hamer, 53, said in an interview at his Northwest Washington townhouse. ‘The research suggests some people have a bit more of that capacity than others, but it’s present to some degree in everybody.’
. . . What he found was that the brain chemicals associated with anxiety and other emotions, including joy and sadness, appeared to be in play in the deep meditative states of Zen practitioners and the prayerful repose of Roman Catholic nuns — not to mention the mystical trances brought on by users of peyote and other mind-altering drugs. At least one gene, which goes by the name VMAT2, controls the flow to the brain of chemicals that play a key role in emotions and consciousness. This is the ‘God gene’ of the book’s title, and Hamer acknowledges that it’s a misnomer. There probably are dozens or hundreds more genes, yet to be identified, involved in the universal propensity for transcendence. . .”
Here is an interview with Hamer, and some responses from chruches here and here.