Deciphering the origins of apomictic polyploids in the Cheilanthes yavapensis complex (Pteridaceae).

Journal Article

Deciphering species relationships and hybrid origins in polyploid agamic species complexes is notoriously difficult. In this study of cheilanthoid ferns, we demonstrate increased resolving power for clarifying the origins of polyploid lineages by integrating evidence from a diverse selection of biosystematic methods. The prevalence of polyploidy, hybridization, and apomixis in ferns suggests that these processes play a significant role in their evolution and diversification. Using a combination of systematic approaches, we investigated the origins of apomictic polyploids belonging to the Cheilanthes yavapensis complex. Spore studies allowed us to assess ploidy levels; plastid and nuclear DNA sequencing revealed evolutionary relationships and confirmed the putative progenitors (both maternal and paternal) of taxa of hybrid origin; enzyme electrophoretic evidence provided information on genome dosage in allopolyploids. We find here that the widespread apomictic triploid, Cheilanthes lindheimeri, is an autopolyploid derived from a rare, previously undetected sexual diploid. The apomictic triploid Cheilanthes wootonii is shown to be an interspecific hybrid between C. fendleri and C. lindheimeri, whereas the apomictic tetraploid C. yavapensis is comprised of two cryptic and geographically distinct lineages. We show that earlier morphology-based hypotheses of species relationships, while not altogether incorrect, only partially explain the complicated evolutionary history of these ferns.

Full Text

Duke Authors

Cited Authors

  • Grusz, AL; Windham, MD; Pryer, KM

Published Date

  • September 2009

Published In

Volume / Issue

  • 96 / 9

Start / End Page

  • 1636 - 1645

PubMed ID

  • 21622350

International Standard Serial Number (ISSN)

  • 0002-9122

Digital Object Identifier (DOI)

  • 10.3732/ajb.0900019

Language

  • eng

Conference Location

  • United States