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Access Type

WSU Access

Date of Award

January 2015

Degree Type

Thesis

Degree Name

M.S.

Department

Biological Sciences

First Advisor

Chuanzhu Fan

Abstract

Abstract

Gene duplication is one of the major mechanisms by which organisms expand their genomes. The material added to the genome can then be acted upon by mutation and natural selection to increase the fitness of the species. By studying these duplicate sequences we can understand the process by which species evolve new functional genes. In a previous paper we identified 100 new duplicate genes through a genome wide comparison between A. thaliana and related species. We selected three of these new duplicate genes and investigated more closely their sequence and expression divergence from their parental gene. The three new duplicate genes selected were AT1G19080, AT1G29410 and AT4G13500 and their parents AT3G55490 AT1G07780 and AT2G05310 respectively. These genes were sequenced using A. thaliana accession lines from a multitude of locations, and the sequences were used in population analyses. The genes were also tested for differential expression patterns. The genes all show evidence of negative selection or a recent population bottleneck. Notably we detected a large number of populations carrying deletions for the new genes. The second set (AT1G07780/ AT1G19080) displayed differential expression, while the third set shows no divergence. The AT4G13500/ AT2G05310 gene family has no known function. In an attempt to discern their function we obtained mutant plants and grew them alongside control plants in an attempt to detect a phenotype for the knockout. We noticed divergent growth patterns between the groups under different light cycles, however they require further testing.

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