  At the cellular level, the book is said to contain “the genetic instructions for the entire repertoire of cellular components” (Collins et al. 2003, p. 3). This genetic determinism at the cellular level is sustained by metaphors of Weismannism and DNA as “code” or “master molecule” (Griesemer 1994; Keller 1994). DNA is accorded causal priority over other cellular components in a couple of ways. One way is to treat DNA as temporally prior. This may be in a physical sense: Weismannism assumes that intergenerational continuity exists only for germ cell nuclei whereas somatic cells and germ cell cytoplasm arise anew in each generation. It may also be in the sense of a point of origin for the transfer of information: the central dogma of molecular biology, which represents a 1950s reformulation of Weismannism in terms of information theory, asserts that information travels unidirectionally from nucleic acids to protein, and never vice versa. The chief difficulty for these claims of temporal priority is of the chicken-and-egg variety: nucleic acids need proteins and other cellular components to make proteins (Smith 1992). Although it is fully accepted that the fertilized ovum contains the cytoplasmic contribution of at least the maternal germ cell, there persists a tendency in developmental genetics to focus on cytoplasmic (mitochondrial) DNA and to ignore the role of cytoplasmic proteins. It is also contentious whether amongst the cell's components only nucleic acids can be said to transmit information: for some philosophers, genetic coding plays a theoretical role at least at this cellular level (Godfrey-Smith 2000); for others, genetic coding is merely (and misleadingly) metaphorical, and all cellular components are potential bearers of information (Griffiths 2001; Griffiths and Gray 1994; Sarkar 1996). An additional way in which DNA is accorded causal priority lies in its treatment as ontologically prior: this is exemplified in Watson's description of DNA as “the most golden of molecules” (in Bodmer and McKie 1994, p. 10). Causal asymmetry provides a possible reason for privileging DNA on an ontological basis: provided all cellular components necessary for protein synthesis are present, modification of the DNA sequence may be followed by a predictable and specifiable change in protein sequence, but the opposite will not occur. This difference could be conceived in terms of the Aristotelian distinction between formal and efficient causation and the accompanying metaphysical preferences for form over matter and mind over body that are deeply embedded in western philosophy. Keller (2000) describes how, in the discourse of “gene action” which arose between the mid-1920s and 1960s and culminated in Francis Crick's “central dogma,” “the gene was bestowed with the properties of materiality, agency, life, and mind” and rendered “[p]art physicist's atom and part Platonic soul” (p.  47).[26]