Master of Science (MS)
Number of Pages
The increase in phenotypic or morphological complexity in organisms may stem from a corresponding increase in the complexity of the underlying genetic architecture, driven by the process of gene duplication. Gene duplication is a mutational mechanism that can impact the genome through the gradual birth and death of individual genes or clusters of genes, and through infrequent episodic events of whole genome duplication. Functional and pleiotropic differences among genes may impact the probability of fixation of duplicated genes and the facility of gene families to record duplication events across deep history. Phylogenetic inference of the relationship among genes in multigene families has been used to reconstruct the history of duplication and subsequently to test hypotheses about the tempo and mode of these mutational mechanisms. We were unable to refute the hypothesis that one or two rounds of tetraploid evolution occurred subsequent to the origin of the lower deuterostomes and immediately preceding the origin of chordates. Our results suggest that the evolutionary history of gene families is defined by the nature of selection on individual genes. Genes embedded in highly constrained pleiotropic networks appear to have different patterns of diversification than genes subject to lesser (or different) selective constraints.
Complexity; Duplication; Gene; Genome; History; Impact; Increasing; Organismal; Patterns
Zoology; Molecular biology; Genetics
University of Nevada, Las Vegas
Ronshaugen, Matthew Rand, "The impact and pattern of gene and genome duplication in the history of increasing organismal complexity" (1997). UNLV Retrospective Theses & Dissertations. 3344.