Patterns and biological implications of DNA content variation in land plants

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Patterns and biological implications of DNA content variation in land plants

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dc.contributor.advisor Newmaster, Steven G.
dc.contributor.author Bainard, Jillian D.
dc.date 2011-10-11
dc.date.accessioned 2011-10-21T18:00:25Z
dc.date.available 2011-10-21T18:00:25Z
dc.date.issued 2011-10-21
dc.identifier.uri http://hdl.handle.net/10214/3078
dc.description.abstract DNA content varies significantly over land plants, and is known to correlate with various aspects of plant form and function. In the present study, two measures of DNA content were examined in taxa across the land plant phylogeny: genome size (or C-value) and endopolyploidy (or endoreduplication index, EI). Additionally, the relationships between DNA content and various morphological and ecological traits were assessed. DNA content was determined for 64 liverwort species from 33 families. There was a large range in 1C-values from 0.27 to 20.46 pg, but no endopolyploidy was observed. There was no correlation between genome size and breeding system (monoecy vs. dioecy). Genome size and degree of endopolyploidy were determined for 74 moss species from 21 families. Genome sizes were constrained in this group, with 1C-values ranging from 0.25 to 1.21 pg. Endopolyploidy was high in all species except from the Sphagnaceae. Additionally, 1C-value was negatively correlated with desiccation tolerance but was not correlated with breeding system. DNA content variation was determined in 31 monilophyte (fern) species (including three horsetails) and 6 lycophyte (clubmoss) species. There was a wide range in 1C-values from 2.79 to 26.90 pg, and there was no indication of endopolyploidy in any of the species. Multivariate analyses were used to explore the relative contribution of traits and phylogenetic placement to DNA content varation in 41 angiosperm species. Six measures of DNA content (2C-value, 1Cx-value, leaf EI, stem EI, petal EI and root EI) were assessed. Phylogeny explained more of the variation observed in the six measures of DNA content than 21 ecological and morphological traits. However, many of the traits were able to explain some of the variation in DNA content, both with and without phylogeny included as a covaraite. One trait that was consistently correlated with DNA content was the association with arbuscular mycorrhizal (AM) fungi. In a controlled experiment, the EI in root cells colonized by AM fungi significantly increased compared to non-mycorrhizal plants. This thesis increases our knowledge regarding the extent and significance of variation in DNA content in land plants. en_US
dc.language.iso en en_US
dc.rights.uri http://creativecommons.org/licenses/by-nd/2.5/ca/ *
dc.subject Genome size en_US
dc.subject Endopolyploidy en_US
dc.subject Bryophytes en_US
dc.subject Lycophytes en_US
dc.subject Monilophytes en_US
dc.subject DNA content en_US
dc.subject Endoreduplication en_US
dc.subject Liverworts en_US
dc.subject Mosses en_US
dc.subject Land plant evolution en_US
dc.subject Angiosperms en_US
dc.title Patterns and biological implications of DNA content variation in land plants en_US
dc.type Thesis en_US
dc.degree.programme Integrative Biology en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department Department of Integrative Biology en_US


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