9629791 Shultz Because they encompass an unparalleled range of structural and taxonomic diversity and have an extremely rich and ancient fossil record, the arthropods (spiders, crabs, insects and their relatives) offer many opportunities for addressing fundamental issues in evolutionary biology. Any meaningful synthesis requires a firm understanding of how the arthropods are related to one another; but the phylogenetic relationships among the major arthropod lineages are difficult to recover. Many different and controversial reconstructions have been proposed. In this study, Jeffrey W. Schultz and Jerome C. Regier will determine whether analysis of the DNA sequences of two slowly-evolving nuclear genes, elongation factor 1a and RNA polymerase II, can provide a more robust phylogenetic reconstruction for arthropods. The researchers will obtain and sequence these genes from a large sample of arthropods representing all major groups, and will analyze these sequences using phylogenetic reconstruction methods. Studies on other organisms have suggested that these genes are appropriate for the analysis of lineages as anciently diverged as the arthropod lineages are thought to be. A more fully resolved phylogenetic tree for arthropods will offer a unique and useful framework for addressing basic questions about the tempo and mode of phylogenetic and structural diversification in arthropods and in other forms of life.
