A grant has been awarded to Drs. Scott Hodges, Elena Kramer, Magnus Nordborg, Jeff Tomkins and Justin Borevitz (of the University of California, Santa Barbara, Harvard University, University of Southern California, Clemson University and University of Chicago respectively) to study adaptation to the environment in the columbine genus, Aquilegia. The evolution of life on earth has been punctuated by numerous examples of adaptive radiation. These dramatic events quickly create a large amount of biodiversity and are evidenced by rapid speciation along with morphological and physiological adaptations to numerous ecological niches. Species in the flowering plant genus Aquilegia have undergone a very recent adaptive radiation and present a unique opportunity to investigate the molecular genetic changes underlying adaptations. Species in this genus have spectacularly different floral morphologies with specializations to different pollinators. In addition, species differ radically in their habitats ranging from coastal forests to desert springs to the high alpine. Because any two species in the genus can be successfully crossed it is possible to dissect the genetic basis for essentially any trait in any species. By developing an array of molecular genetic resources for this genus, this project will provide the infrastructure for a host of studies by a broad community of scientists. Comparative genomic studies will be particularly amenable because Aquilegia is a member of the basal eudicot family Ranunculaceae, which is nearly equidistant between the eudicot model systems such as Arabidopsis and the monocot model systems such as rice. All of these studies will be facilitated by the fact that the genome of Aquilegia is among the smallest for a flowering plant at about 350 Mbp.
The specific goals of this project are to evaluate the genetic basis of three important traits, morphological adaptation to a specific pollinator, physiological adaptation for flowering time and adaptation to different soil/habitats. These goals will be accomplished by developing a physical map of the genome of one species of Aquilegia, A. formosa, along with a large-scale EST sequence database and a transformation system. The EST sequences will be localized to the physical map and used to construct oligonucleotide arrays for expression studies and array-based mapping of traits. Fine-mapping and cloning of a locus affecting flower orientation will be accomplished with array-based mapping along with association mapping and expression studies. To investigate the evolution of flowering time in Aquilegia, candidate genes will be cloned and their expression patterns and evolution will be characterized. To determine the genetic architecture for adaptations to different habitats, recombinant inbred lines from a cross between A. formosa and A. pubescens will be created, their breakpoints finely mapped and their fitness determined in each parental species' habitat.
