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Hamer decided to use the data he gathered in the smoking survey to conduct a little spirituality study on the side. First he ranked the participants along Cloninger's self-transcendence scale, placing them on a continuum from least to most spiritually inclined. Then he went poking around in their genes to see if he could find the DNA responsible for the differences. Spelunking in the human genome is not easy, what with 35,000 genes consisting of 3.2 billion chemical bases. To narrow the field, Hamer confined his work to nine specific genes known to play major roles in the production of monoamines--brain chemicals, including serotonin, norepinephrine and dopamine, that regulate such fundamental functions as mood and motor control. It's monoamines that are carefully manipulated by Prozac and other antidepressants. It's also monoamines that are not so carefully scrambled by ecstasy, LSD, peyote and other mind-altering drugs--some of which have long been used in religious rituals.
Studying the nine candidate genes in DNA samples provided by his subjects, Hamer quickly hit the genetic jackpot. A variation in a gene known as VMAT2--for vesicular monoamine transporter--seemed to be directly related to how the volunteers scored on the self-transcendence test. Those with the nucleic acid cytosine in one particular spot on the gene ranked high. Those with the nucleic acid adenine in the same spot ranked lower. "A single change in a single base in the middle of the gene seemed directly related to the ability to feel self-transcendence," Hamer says. Merely having that feeling did not mean those people would take the next step and translate their transcendence into a belief in--or even a quest for--God. But they seemed likelier to do so than those who never got the feeling at all.
Hamer is careful to point out that the gene he found is by no means the only one that affects spirituality. Even minor human traits can be governed by the interplay of many genes; something as complex as belief in God could involve hundreds or even thousands. "If someone comes to you and says, 'We've found the gene for X,'" says John Burn, medical director of the Institute of Human Genetics at the University of Newcastle in England, "you can stop them before they get to the end of the sentence."
Hamer also stresses that while he may have located a genetic root for spirituality, that is not the same as a genetic root for religion. Spirituality is a feeling or a state of mind; religion is the way that state gets codified into law. Our genes don't get directly involved in writing legislation. As Hamer puts it, perhaps understating a bit the emotional connection many have to their religions, "Spirituality is intensely personal; religion is institutional."