POLYPHYMON · Polytrichales: towards a modern phylogenetic monograph and the development of a model of sporophyte evolution
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2007-02-01 → 2009-01-31
- EU contribution
- €164,268
- Participants
- 1
- Scheme
- EIF
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Results in brief
Final Activity Report Summary - POLYPHYMON (Polytrichales: Towards a modern phylogenetic monograph and the development of a model of Sporophyte evolution)
Mosses are the second most diverse group of land plants after the flowering plants or Angiosperms, and yet are relatively little studied. The Polytrichopsida are one of the major groups of mosses, with fewer species than the largest group, the Bryopsida, but considerable variety of form. Some species are very large for mosses with well developed vascular systems and are abundant in certain habitats. The Polytrichopsida represent an evolutionary counterpart to the Bryopsida, with many unique features as well as others that are also found outside of the group but may have evolved independently. In this project we used molecular sequences from all three genomes (nuclear, chloroplast and the mitochondrial) as well as some novel features of the sporophyte (particularly the peristome, the structure that regulates spore release) to construct a model of the evolutionary history of the group (a phylogeny). We also made an extensive study of the peristome to determine how it has evolved within the Polytrichopsida and to discover whether it is an independent development or homologous to superficially similar structures found in other mosses. Our results show that the earliest lineages in the group all lack peristomes and that the Polytrichopsidan peristome has arisen subsequently, i.e. it is not derived from the precursors of the structurally rather different peristomes found in the Bryopsida. We also discovered many surprising new relationships within the group, including ones that demonstrate convergent evolution of the morphology corresponding to the genus Oligotrichum in northern and southern hemisphere temperate areas and the artificiality of the genus Polytrichastrum. Our molecular results were incongruent (i.e. they disagreed) on some key aspects of the phylogeny. One possible explanation for this is that the nuclear genome has a slightly different evolutionary history from the chloroplast and mitochondrial genomes due to occasional past hybridisation between lineages that have now diversified into different groups but were once more similar; we were able to explain the incongruence between our datasets in terms of four hypothesised events of this type. Extensive new information about peristome structure additionally provides an entirely new source of data for understanding the development of this apparatus within the group, as well as some aspects of its function. Our results are being formulated in terms of a comprehensive classification. This is the foundation of an ongoing database project that will be made available online as a primary resource for information about the group.
Data: CORDIS, © European Union
Project objective
I aim to produce a comprehensive taxonomic treatment of the hair-cap mosses (order Polytrichales), based on state-of-the-art phylogenetic inference techniques. I will sample a wide range of morphological and molecular characters and incorporate novel data from sporophyte microstructure and cell wall chemistry. A major output will be a comprehensive, Internet accessible database of taxa.The Polytrichales is one of the most phylogenetically isolated moss lineages and a significant group of land plants in its own right. A synopsis of the largest genus, Pogonatum, provides a baseline for evaluating the extent of the work required for a similar treatment of the entire order. It is estimated that ca. 87% of the 1588 published names are synonyms, and that the actual number of species is ca. 200.The systematic treatment will follow that of earlier studies by Prof. Hyvonen, which include phylogenetic analyses using data from morphology and 7 genomic regions. I will enlarge upon these to sample all species within the order, thus initiating the most comprehensive phylogenetic analysis of any major moss group to date. In previous unpublished work I identified novel features of the polytrichalean sporophyte that challenge recent taxonomic treatments and offer insights in to structure, function and evolution.These will be investigated as part of a detailed study using scanning electron microscopy that will contribute towards compartmentalised datasets of gametophyte and sporophyte characters, allowing controlled testing of hypotheses of comparative phylogenetic vs. Concerted homoplastic signal.The project will considerably develop my research career by allowing me to gain expertise in a group other than that studied for my PhD (Prof. Hyvonen is the foremost world authority on the Polytrichales) and providing me with extensive training in new phylogenetic and other methods, including optimisation alignment, parallel computing, electron micrography and bioinformatics.
Original text from CORDIS.
Participants
- UNIVERSITY OF HELSINKI · HELSINKICoordinatorFinland
Links
Data: CORDIS, © European Union