 Context-dependence is primarily a problem for models of theory reduction; some models of explanatory reduction take the organismal context for granted without being committed to reducing it molecularly (as seen in explanations offered in developmental biology). Sciences can avail themselves of  causes as difference makers  relative to a given causal context (Waters 2007, Woodward 2003). Both experimental investigation and explanation can focus on one among many causes, relegating everything else to the context or background (which is often held fixed in experimental studies). For example, if the loss in function of a particular gene leads to an abnormal phenotype in a knock-out experiment, this gene is one causal factor implicated in the development of the normal phenotype. Explanations appealing to this gene—as a salient causal factor relative to a context—are genuinely explanatory even if other genes involved in the phenotype are unknown and the cellular context for the gene is not yet understood (Waters 1994, 2007). If molecular biologists discover that the same mechanism produces different effects in distinct contexts and only one of these effects is the target of inquiry, a part of the mechanism’s context becomes epistemically relevant and can be included in the explanation (Delehanty 2005).