1064 THE STRUCTURE OF EVOLUTIONARY THEORY
most interior female carpels. Moreover, leafy, a "higher control" gene previously
recognized as an initiator or suppressor of floral growth and placement in general
(Weigel and Nilsson, 1995), apparently also regulates the more specific operation of
the ABC series. (Busch et al., 1999, demonstrate that a protein produced by leafy
bonds directly to a particular DNA segment of a C gene responsible for the
generation of carpels.)
This model enjoys obvious significance for the full gamut of evolutionary
issues, ranging from the most theoretical (in "updating" Goethe's formalist theory
(see pp. 281-291) that all parts regulated by the ABC series conform to a generalized
"leaf" archetype), to the most practical (hopes of florists to enhance AB interactions
and grow flowers with larger and more numerous petals). But in the present context, I
merely wish to highlight a linguistic point: the selected terminology of ABC surely
encapsulates the accurate impressions (and the excitement) of researchers who
recognize their role as pioneers engaged in the construction of a basic alphabet for a
new understanding of nature.
The pure discoveries of evo-devo may fit the heroic image of science as con-
queror of previous ignorance (the tabula rasa model of light upon previous darkness
or, literally, the first writing on a blank slate). But the most stunning of scientific
novelties surely gain their status by virtue of their unexpected or surprising
character—that is, their failure to match, or even their power to mock, the anticipated
constitution of a part of the natural world previously
10 - 12. The elegant simplicity of the ABC model, from Weigel and Meyerowitz, 1994. In this
model, based upon the genetics and development of Arabidopsis, the four circlets of sepals,
petals, stamens, and carpels achieve their distinctive forms under the following influences, as
shown in the diagram. A genes determine the development of sepals; A and B petals; B and C
stamens; and C alone, carpels.