Systematics of Woodsia: Ferns, bioinformatics and more
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Ferns are one of the three main clades of vascular plants. They have few easily studied morphological characters, reflected in a historically unstable classification. The fern genus Woodsia is known to have a complex evolutionary history including numerous polyploid taxa and hybrids. It is a cosmopolitan group of small rock loving ferns mainly found in montane areas.
This thesis aims at analyzing the patterns of diploid and polyploid evolution in Woodsia and to resolve and classify the relationships of Woodsiaceae and the other families in the large fern clade Eupolypods II.
The Eupolypods II family relationships were inferred with DNA sequences from 81 specimens representing all major lineages. This resulted in the first well supported phylogeny of this clade and revealed Woodsiaceae to be non-monophyletic. The genera previously placed in this family were reclassified into five new or resurrected families. Swedish fern genera that have changed family classification are Woodsia (hällebräknar), now in the monogeneric family Woodsiaceae, Athyrium (majbräknar), now in Athyriaceeae and Cystopteris (stenbräknar) and Gymnocarpium (ekbräknar) now in Cystopteridaceae.
To analyze the evolution of Woodsia, phylogenies were produced from five plastid and two nuclear regions sequenced from 188 specimens. The results show that most taxa in Woodsia are polyploid. Polyploidization is the most common mode of speciation in the genus with an estimated polyploid speciation rate of 54%. The polyploids are mostly young and many of the polyploid taxa seem to have formed multiple times. The results also address several taxonomic and biogeographic questions.
In the process of the work we made methodological advancements and developed 20 new low copy nuclear marker regions as well as a software pipeline for finding primers in transcriptome datasets. The alignment editor software AliView was developed for handling the increasing size datasets in a user friendly way.
In conclusion this thesis provides new insights into the complexities of the evolution of a fern genus in which much of the diversity is accommodated in young species formed through polyploidization. It provides a framework of phylogenetic relationships at different levels that both answers long standing questions and generates new ones.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. , 36 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1182
ferns, Eupolypods II, Woodsia, phylogeny, biogeography, polyploidy, polyploid speciation, classification, alignment
Research subject Biology with specialization in Systematics
IdentifiersURN: urn:nbn:se:uu:diva-232233ISBN: 978-91-554-9040-9OAI: oai:DiVA.org:uu-232233DiVA: diva2:747587
2014-10-31, Lindahlsalen, Norbyvägen 18B, Uppsala, 10:00 (English)
Brysting, Anne Krag, Professor
Korall, Petra, Associate professorThulin, Mats, Professor
FunderSwedish Research Council Formas, 2006-429 and 2010-585
List of papers