In order for animals to detect food sources, avoid predators and find mates, they rely on their olfactory system, or sense of smell. The ability to detect and distinguish among thousands of environmental odorants is based on a combinatorial recognition system. A specific smell is coded in the brain by a specific combination of receptor proteins that get stimulated by the unique combination of odorant chemicals elicited by that scent. "The smell of 'lemons,' for example, would result from a specific combination of odorant receptor proteins that become stimulated upon binding the specific set of inhaled chemicals emitted from a…