9806792 McMillan Despite the central position of adaptation in biological research, the genetic basis of adaptation in natural populations remains poorly explored. This is primarily because, except for a few model genetic organisms like mice and fruit flies, the many genetic markers necessary for detailed genetic analysis of adaptive traits have not been developed. This project will map genes involved in color pattern change in the neotropical butterfly Heliconius erato. Within this species, there has been remarkable evolution into over 20 geographic races that show striking differences in wing color patterns. The vivid wing patterns of H. erato are adaptations that warn potential predators of the butterflies' distastefulness. A detailed genetic map of H. erato will provide a potent framework for studying the number, phenotypic effect, and position of both major and minor color pattern genes underlying the color pattern change in this species. Moreover, the reference genome map will allow important regulatory genes emerging from developmental genetic studies of insects to be mapped relative to the genes known to cause pattern change in H. erato. Markers and theory developed in this project will be generally useful for other studies of Lepidoptera, which comprise almost 10% of the world's species and include some of the most noxious pests of food and fiber. The presence of a well defined developmental model underlying pattern evolution makes butterfly wings excellent models for integrating genetics, development, and morphological change. This study will be the initiating step in future comparative linkage analysis of the architecture of color pattern mimicry between H. erato and H. melpomene. Heliconius melpomene has undergone a parallel intraspecific color pattern radiation, such that races of the two distantly related species share nearly identical wing patterns across much of South and Central America. Understanding the genetic changes that repeatedly produced such remarkable converg ence in the wing patterns of these two species offers biologists rare insights into the evolution of mimicry and into the links between development and adaptive change.
