An isolated and purified nucleic acid comprising a gene specifically expressed in hop lupulin glands. Hops are dioecious, and only female plants bear cones, the lupulin glands of which contain secondary metabolic products which provide bitterness and flavor to beer. These secondary metabolic products contain some pharmacologically effective compounds. In order to breed a more useful cultivar of hops by manipulating the constituent of such useful secondary metabolic products relying on genetic engineering techniques, this invention provides an isolated and purified nucleic acid comprising a gene specifically expressed in hop lupulin glands. By using this nucleic acid, it is possible to develop a novel method for breeding hops with transformation techniques and molecular selection techniques. Furthermore, the present invention also provides a nucleic acid comprising the regulatory region for specifically expressing genes in lupulin glands. This nucleic acid can be used also for hop breeding.