  It has been proposed that the real reason biologists center attention on genes and DNA is that genes are difference makers that can be used to trace and manipulate a broad range of biological processes (Waters 2004a and 2006). This scientific practice makes sense independently of any fundamental theory associated with molecular genetics. In the case of molecular genetics, it is investigative pragmatics, not fundamental theorizing, that drives scientific research. The basic theory suffices to explain the investigative utility and results of gene-centered approaches. The fundamental theory is, in an important sense, epiphenomenal with respect to the design and implementation of gene-centered research. On this view, the role of the fundamental theory should be understood in Latourian terms (1987, 1988), as a platform for rallying the troops and bringing resources to research endeavors.  The design of the laboratory experiments and the reason why the experiments work, can be explained in terms of broad investigative strategies, the basic causal theory of molecular genetics, and the details of the experimental contexts.