The article reports on the acquisition of Sirna Therapeutics Inc., a ribonucleic acid interference (RNAi) firm in California, by pharmaceutical company Merck and Co. Inc. in New Jersey. According to Peter Kim, president of Merck Research Laboratories, RNAi could change the way the company goes about discovering and developing drugs. The number of patent applications for RNAi has increased over 3,000 percent between 2000 and 2003.