Date of Award

1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Chunguang Du

Committee Member

John J. Gaynor

Committee Member

Ann Marie Dilorenzo

Abstract

Centromeres are playing a key role in proper segregation of sister chromatids during mitosis and meiosis. At the centromere region in the chromosome, spindle microtubules attached to the kinetochores that direct the chromosome segregation during mitosis and meiosis. Although centromeric function is conserved among different organisms, there is no conservation of centromeric DNA sequences ranging from budding yeast which has a consensus sequence of approximately 125 base pairs (bp) on each chromosome to Caenorhabditis elegans species which has a holocentric centromere that spans the entire chromosome. However, there are some common proteins that form the kinetochore, such as CENH3 and CENP-C.

In this study, wild rice (Oryza ruflpogon) chromosome 8 centromere fragments were compared to all the domesticate rice {Oryza sativa ssp japónica) chromosome centromeres, Arabidopsis thaliana chromosome 5 centromere, Lycopersicon esculentum chromosome 12 centromere, and Dictyostelium discoideum chromosome centromere. Annotation results of all the genomes suggest that many of the structural aspects parallel in both the species of the rice centromeres. For example, both wild rice fragments and domesticated rice chromosome centromere sequences found to share their GC contents in between 40-45%. The Arabidopsis thaliana chromosome 5 centromere, the Lycopersicon esculentum chromosome 12 centromere, and the Dictyostelium discoideum chromosome centromere had less structural similarities with the Oryza rufipogon chromosome 8 centromere. Further, annotation of the wild rice fragments and the domesticated rice genome revealed that both the species had the cento satellite repeats and Ty3/gypsy retrotransposons.

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