Phylogenetic relationships amongPinus species (Pinaceae) inferred from different numbers of 6PGDH loci

Electrophoretic examination of variousPinus species from both subgenera revealed that several taxa differ in the number of loci that control the enzyme system 6-phosphogluconate dehydrogenase (6PGDH). Based on inheritance analyses and published data, it was established that all species of subg.Pinus possess only two 6PGDH loci, whereas all stone pines of subg.Strobus exhibit four controlling loci. In order to trace the phylogenetic links at which one or two gene duplications occurred during pine evolution, several species of subsect.Strobi (sectionStrobus) and two species of sect.Parrya were additionally investigated. Based on conclusions about the uniqueness of gene duplications and the different numbers of 6PGDH loci, a phylogenetic tree of the pine taxa was constructed. This tree shows some new features not recognized in earlier studies and supports several novel assignments postulated in very recent pine classifications.