RUI: Molecular Systematics of the Conifers: Chloroplast DNA Structural Evidence

Central Washington University, Ellensburg WA

Investigators

Abstract

0075700 Raubeson The cone-bearing plants or conifers, including pines, firs, junipers, cypresses, and relatives, number in the several hundred species of living plants, disposed in 60 or so genera, and are the surviving members of an evolutionary lineage that dominated terrestrial environments in the Mesozoic. Genealogical relationships among these surviving groups are not yet firmly established, although gene sequence data are accumulating for many representative taxa. Dr. Linda Raubeson is contributing new structural genomic data to help answer questions about the phylogenetic relationships of conifers. In particular, she is studying the content and order of genes in the chloroplast genome of a sample of 20 or so genera of conifers, and including the likely related ginkgo and gnetophytes. Fine-scale restriction-enzyme mapping of mutations along the chloroplast genome will reveal changes in gene order (inversions or translocations) and gene losses or duplications, some of which have already been characterized in her laboratory. Most of these structural mutations are of rare occurrence, and are likely to mark groups of phylogenetically related genera, thus providing new evidence for taxonomic and classification studies. The chloroplast genome maps, in turn, will aid more detailed studies of species-level relationships in taxonomically problematic groups, either by gene sequencing or yet finer scale restriction-enzyme mapping. Throughout the project, as in past work by Dr. Raubeson, undergraduate students will participate in discrete activities targeted to provide them training in modern molecular phylogenetic methods and experience in the design and execution of a research activity.