A novel multigene family may encode odorant receptors: A molecular basis for odor recognition.

"In their landmark paper published in 1991, Buck and Axel cloned olfactory receptors, showing that they belong to the family of G protein coupled receptors. By analyzing rat DNA, they estimated that there were approximately one thousand different genes for olfactory receptors in the mammalian genome. This research opened the door to the genetic and molecular analysis of the mechanisms of olfaction" (Wikipedia article on Richard Axel, accessed 7-22).

In 2004 Axel and Buck received the Nobel Prize in Physiology or Medicine "for their discoveries of odorant receptors and the organization of the olfactory system."