Genetic Analysis of the Newly Found Diploid Cytotype of Deparia petersenii (Woodsiaceae: Pteridophyta): Evidence for Multiple Origins of the Tetraploid

According to the most recent monograph of the genus Deparia, Deparia petersenii is a species in the section Athyriopsis, which is one of the four sections of the genus Deparia. Because few diploids have been reported in the section Athyriopsis, no studies attempting to deduce how polyploid Athyriopsis species have originated have been conducted. We report here on the genetic structure and relationships of diploid D. petersenii, which is a new cytotype we discovered in Taiwan. Although the diploid populations have extensive morphological variation, the results of isozyme analysis indicate that the diploid plants belong to a single biological species. We examined the genetic relationship between the diploids and the other cytotypes (tetraploid and hexaploid) by sequencing variable chloroplast DNA regions (rbcL and ndhF). Two major haplotypes found in the diploids were shared with some of the tetraploids. Therefore, we concluded that the tetraploid D. petersenii has evolved from the diploid at least twice. The extensive morphological variation seen in tetraploid D. petersenii may have been inherited from the diploid.