Like caffeine? There's a gene for that -- two of them, actually

Attention coffee drinkers: If you think your craving for a cuppa joe stems from sleepiness, habit or simply a desire to make Starbucks CEO Howard Schultz an even richer man, you are sorely mistaken. A team of researchers from Harvard, the National Cancer Institute and other esteemed institutions of biological science reports that our need for caffeine is in our DNA. As if there were any part of our lives that weren’t subject to genetics in some form or fashion.

But back to the so-called caffeine genes. There are two of them, according to a report published Tuesday in PLoS Genetics.The first is CYP1A2, which had already been known to have something to do with caffeine metabolism, and the second is AHR, which plays a role in regulating CYP1A2.

Everyone has both of these genes, of course, but we don’t all have the exact same kinds. Those in the study who had the most caffeine-seeking version of CYP1A2 drank an average of 38 milligrams more of the stuff each day than those with the most caffeine-indifferent version. People with the most caffeine-dependent version of the AHR gene consumed an average of 44 mg. more per day than their counterparts with the least caffeine-seeking version.