The embrace of informational and other semantic concepts has been especially marked within genetics, and other fields—evolutionary theory and developmental biology—with strong ties to genetics. But informational language is not only found there: for example, hormones are routinely seen as long distance signals that enable one organ system to coordinate with others (Levy 2011). That said, the usage that has generated the most discussion is found in the description of the relations between genes and the various structures and processes to which genes contribute. For many biologists, the causal role of genes should be understood in terms of their carrying information about their various products; and perhaps as well about the environments in which these products enhance fitness (Lorenz 1965; Shea 2013). The expression of that information might depend on the presence of various environmental factors, but the same can be said of other kinds of message. Breaking things down further, we can recognize two causal roles for genes, and hence two potential explanatory roles for genetic information, within biology. Genes are crucial to both explaining the development of individual organisms, and to explaining the inheritance of characteristics across generations. Information has been invoked in both explanatory contexts.