New genomic tools for molecular studies of evolutionary change in threespine sticklebacks

The dramatic radiation of sticklebacks in different post-glacial environments provides a unique opportunity to study the molecular mechanisms that underlie rapid evolutionary change in vertebrates. We have developed a number of genomic and genetic tools to facilitate further study of a wide range of morphological, physiological and behavioral traits in sticklebacks. A large collection of microsatellite markers has previously been developed for use in genome-wide linkage mapping of interesting traits in crosses between different stickleback forms. cDNA libraries have been generated and EST sequencing projects have begun to isolate stickleback homologs of developmental control genes. Large insert BAC libraries have been built to compare chromosome regions of interest from both anadromous and freshwater stickleback populations. Large scale fingerprinting of one of these libraries has been used to assemble overlapping contigs of BAC clones for chromosome walking and positional cloning. Together with recent development of methods to make transgenic sticklebacks, these tools should make it possible to identify the molecular basis of many different evolutionary traits in stickleback, and to begin to answer longstanding questions about the numbers and types of mutations that control the appearance of new morphological, physiological, and behavioral traits during vertebrate evolution.