  Gene skeptics claim that there is no coherence to the way gene is used at the molecular level and that this term does not designate a natural kind; rather, gene is allegedly used to pick out many different kinds of units in DNA. DNA consists of “coding” regions that are transcribed into RNA, different kinds of regulatory regions, and in higher organisms, a number of regions whose functions are less clear and perhaps in cases non-existent. Skepticism about genes is based in part on the idea that the term is sometimes applied to only parts of a coding region, sometimes to an entire coding region, sometimes to parts of a coding region and to regions that regulate that coding region, and sometimes to an entire coding region and regulatory regions affecting or potentially affecting the transcription of the coding region. Skeptics (e.g., Burian 1986, Portin 1993, and Kitcher 1992) have concluded, as Kitcher succinctly puts it: “a gene is whatever a competent biologist chooses to call a gene” (Kitcher 1992, p. 131).