A Phylogeny of Pinus [Pinaceae] Based on Six Low-Copy Nuclear Genes

Oregon State University, Corvallis OR

Investigators

Abstract

A grant has been awarded to Dr. Aaron Liston at Oregon State University and Dr. Richard Cronn at the USDA Forest Service to investigate evolutionary and genetic relationships among the approximately 100 species of pine trees (the genus Pinus). Pines are the most widespread genus of woody plants native to the Northern Hemisphere, and are widely planted in the Southern Hemisphere. Thus pines are of vast economic and ecological importance worldwide. Past studies of pine evolutionary relationships have produced conflicting results, and no more than half of all species have been included in any single analysis. To address these problems, Liston and Cronn will use genomic data emerging from research on loblolly pine to identify twenty-five nuclear genetic markers for screening DNA-level variation across the genus. The six most promising markers will be used to construct a multi-gene estimate of evolutionary relationships for all available pine species, and to identify the source of conflict among existing studies. The potential for transferring these markers to phylogenetic studies of other gymnosperm genera will also be examined. The resolution of systematic relationships among pine species will result in an enhanced understanding of their evolutionary history, and contribute to an improved classification of the genus. Furthermore, these results will provide a robust foundation for studies of pine ecology and evolutionary biology. By determining which species are most closely related, the results should contribute to efforts focused on the genetics and breeding of pine species. It is also anticipated that the genetic markers developed here will be useful in similar studies of other gymnosperm genera. Two graduate and two undergraduate students will be supervised by Liston and Cronn, and receive training in the field of plant molecular systematics.