Jumping genes and AFLP maps: transforming lepidopteran color pattern genetics Jeffrey M. Marcus Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA Correspondence: (email: jeffrey.marcus@wku.edu) SUMMARY The color patterns on the wings of lepidopterans are among the most striking patterns in nature and have inspired diverse biological hypotheses such as the ecological role of aposomatic coloration, the evolution of mimicry, the role of human activities in industrial melanism, and the develop- mental basis of phenotypic plasticity. Yet, the developmental mechanisms underlying color pattern development are not well understood for three reasons. First, few mutations that alter color patterns have been characterized at the molecular level, so there is little mechanistic understanding of how mutant phenotypes are produced. Second, although gene expression patterns resembling adult color patterns are suggestive, there are few data available showing that gene products have a functional role in color pattern formation. Finally, because with few exceptions (notably Bombyx), genetic maps for most species of Lepidoptera are rudimentary or nonexistent, it is very difficult to characterize spontaneous mutants or to determine whether mutations with similar pheno- types are because of lesions in the same gene or different genes. Discussed here are two strategies for overcoming these difficulties: germ-line transformation of lepidopteran species using transposon vectors and amplified frequency length polymorphism-based genetic mapping using variation between divergent strains within a species or between closely related and interfertile species. These advances, taken together, will create new opportunities for the characterization of existing genetic variants, the creation of new sequence- tagged mutants, and the testing of proposed functional genetic relationships between gene products, and will greatly facilitate our understanding of the evolution and development of lepidopteran color patterns. INTRODUCTION Lepidopteran wing color patterns are among the most at- tractive model systems for exploring the relationship between development and evolution. They are interesting evolution- arily because at least some patterns are clearly associated with fitness benefits associated with natural or sexual selection, playing roles in the evolution of mimicry (Clarke and Shep- pard 1960), the phenomenon of industrial melanism (Kettle- well 1973), the development of aposematic coloration (Brower 1958), and the manifestation of phenotypic plasticity (Windig 1994). These patterns are also particularly suitable for study because they are highly variable, consist of clearly defined subunits, exist in two dimensions, and are structurally simple (Nijhout 1991; Brakefield 1996; Beldade and Brakefield 2002). For these reasons, many researchers with interests in modeling developmental processes have studied butterfly col- or patterns. Early models used generalized mechanisms of pattern formation (e.g., lateral inhibition, reaction-diffusion, diffusion gradient, and threshold responses) to make predic- tions about how color patterns will vary as parameters of the model are changed. Such models have been used as the basis for simulations of the microevolution of color patterns (Ni- jhout and Paulsen 1997), for understanding fluctuating asym- metry in terms of classical quantitative genetic theory (Klingenberg and Nijhout 1999), to test the suitability of proposed groundplans as a basis for understanding the ev- olution of pattern polymorphisms (Sekimura et al. 2000), and to understand the responses of wing patterns to surgical perturbations (Brakefield and French 1995; French and Brakefield 1995; Monteiro et al. 2001). Some of the more recent models propose regulatory inter- actions between specific gene products to account for the dif- ferentiation of particular color patterns (Fig. 1). The genetic hierarchies proposed by these models have been used to ex- plain phenomena such as the formation of eyespots (Brake- field et al. 1996; Brunetti et al. 2001), melanic polymorphisms in butterflies (Koch et al. 1998), scale formation (Reed 2004), and the conservation of regulatory networks and their co- option for different functions across species (Keys et al. 1999). These genetic models have relied heavily on the study of expression patterns of candidate genes identified primarily from Drosophila melanogaster and with only a few exceptions (Lewis et al. 1999; Weatherbee et al. 1999), gene products EVOLUTION & DEVELOPMENT 7:2, 108–114 (2005) & BLACKWELL PUBLISHING, INC. 108