Robert Margolskee, director of the Monell Chemical Senses Center in Philadelphia, doesn’t like coffee, dark chocolate, or bitter beer. Since he heads a preeminent scientific institution dedicated to studying taste and smell, it’s not surprising that he can explain exactly why that is the case. Blame it on genetics, says Margolskee, who has a doctorate in molecular genetics as well as a medical degree. The researcher says he was recently genotyped and found that he possesses a partic…