Neopolyploid establishment and evolution


Oswald, Benjamin Paul.. (2010). Neopolyploid establishment and evolution. Theses and Dissertations Collection, University of Idaho Library Digital Collections.

Neopolyploid establishment and evolution
Oswald, Benjamin Paul.
Polyploidy Mutation (Biology)--Evolution
Bioinformatics & Computational Biology
Despite the well-documented historical importance of polyploidy, the mechanisms responsible for the establishment and evolutionary success of novel polyploid lineages remain unresolved. One possibility, which has not been previously evaluated theoretically, is that novel polyploid lineages are initially more resistant to pathogens than the diploid progenitor species. Another possibility is that polyploidization results in immediate divergence of phenotypic characters, and may alter the phenotypic and genotypic associations between traits, i.e. the P and G matrices. In combination with factors such as competition, assortative mating, reproductive assurance, and stabilizing selection, establishment and coexistence may be plausible. Here we explore neopolyploid establishment and evolution in three ways: (1) by developing and analyzing mathematical models of interactions between newly formed polyploid lineages and their pathogens; (2) by studying the perennial plant Heuchera grossulariifolia and measuring phenotypic divergence and changes in the phenotypic and genotypic covariance matrices caused by neopolyploidization; and (3) by developing a model of polyploid establishment using individual based simulations that explores how changing environments facilitate polyploid evolution. We find, that for the genetic mechanisms of pathogen resistance with the best empirical support, newly formed polyploid populations of hosts are expected to be more resistant than their diploid progenitors. Our results also reveal that polyploidization causes immediate divergence for traits relevant to establishment and results in significant changes in the structure of the phenotypic covariance matrix. In contrast, our results do not provide evidence that polyploidization results in immediate and substantial shifts in the genetic covariance matrix. Our model shows that polyploid establishment and coexistence with diploids is likely using observed values for parameters, and without the polyploid lineage needing a fitness advantage. We further predict that polyploid lineages will have an increased opportunity for replacement of their diploid progenitors in cases where the environment changes rapidly.
Thesis (Ph. D., Bioinformatics and Computational Biology)--University of Idaho, May 2010.
Major Professor:
Scott L. Nuismer.
Defense Date:
May 2010.
Format Original:
viii, 97 leaves :ill., map ;29 cm.

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