Pines as model gymnosperms to study evolution, wood formation, and perennial growth

Pines provide a model system for the gymnosperms, an old and successful gro up of vascular plants that last shared a common ancestor with the angiosper ms about 285 million years ago. Gymnosperms are distinct from angiosperms i n their reproduction, development, metabolism, adaptations, and evolution. Pines cover vast areas of the globe, are one of the most important genera o f forest trees, dominate the ecology of many temperate and subtropical fore st ecosystems, and provide a major fraction of the world's wood. Here, we s ummarize many features of pine that make it a useful model for gymnosperms and woody plants. We also describe the influence of its reproductive system on methods for genetic analysis and the prospects for genomic studies and genetic engineering. Pines are limited as model systems by their long gener ation times, large size, large genomes, and the long time from fertilizatio n to seed set.