To understand evolution the buck stops at the DNA, since the characters that differ between species that have a common ancestor are heritably encoded in their different DNA genomes. The Davidson laboratory has designed experiments to determine what really happened in a specific case of evolution that can be analyzed experimentally at the DNA level. They argue that the most interesting evolutionary features are those that control development of the body plan and that while there is much hand-waving about evolution, there are few cases where one can put one''s finger directly on the sequences that cause specific differences. They also propose that these differences are almost always in the modular control sequences that specifically determine where, when and how intensely genes are expressed in response to cellular regulatory state. The Davidson laboratory will focus on developing sea urchins and sea stars, which had a common ancestor about a half billion years ago and whose developmental control systems include several cases where comparisons reveal the same genes doing very different things. This differential regulation results in two kinds of embryos that are, in some respects, quite distinct in form and function. The Davidson laboratory has developed the technology to uncover the differences that matter in these control systems, and to convert them into one another experimentally. Nuts and bolts knowledge of evolution is not only basic to understanding our own and all other animals'' biology at a mechanistic level, but will have a gigantic practical payoff. Evolution is our only natural laboratory for change in genomic control systems. To re-engineer these systems for therapeutic or other benign purposes, will require that we learn the rules of allowed and forbidden change in these systems. The Davidson laboratory has significant broader impacts on the developmental biology community by developing new approaches and technologies and for pioneering work on unraveling gene regulatory circuitry during development. The laboratory also has a strong record of student training and participates in the Caltech''s summer SURF program for undergraduates.
