Establishment of tribolium as a genetic model system and its early contributions to evo-devo.

IN the fall of 1986 my colleague, Dick Beeman, sat in my office at Kansas State University and told me a fascinating story. He worked at what was then called the U. S. Grain Marketing Research Laboratory, a U. S. Department of Agriculture facility about a mile from campus. He was trained as an insect toxicologist, but to aid in his research he had become a self-taught geneticist using the red flour beetle, Tribolium castaneum. Beeman told me about interesting data he had regarding the juxtaposition in Tribolium of the apparent orthologs of genes in the Antennapedia and bithorax complexes (Beeman 1987). He had heard me speak about the Drosophila complexes and recombinationally mapped putative orthologs in Tribolium. This interaction inspired my involvement, with many others, in the development of Tribolium as a genetic model system, and the use of this beetle for work on the evolution of developmental mechanisms (evo-devo). I will provide evidence that Tribolium now represents the third best (after Drosophila and Caenorhabditis) invertebrate for genetic and molecular studies. I will argue for the importance of genetically tractable insect systems other than Drosophila, especially given the derived nature of fly morphology. Although it is specialized in many ways, Tribolium is nevertheless relatively ancestral with regard to many morphological features and developmental events. Somewhat artificially, I am going to separate its growth as a model system from its contributions to evo-devo, where I will concentrate on studies of the Hox cluster. EARLY TRIBOLIUM STUDIES