Date of Award

2022

Degree Type

Open Access Thesis

Document Type

Master Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Patrick J. Calie

Department Affiliation

Biological Sciences

Second Advisor

Mostafa Rahnama

Department Affiliation

Biological Sciences

Third Advisor

Stephen C. Richter

Department Affiliation

Biological Sciences

Abstract

The telomeres of M. oryzae can experience unique rearrangements within a single generation. These rearrangements are frequently attributed to the presence of two retrotransposons (MoTeR 1 and MoTeR 2) that are endemic to the telomeres. These rearrangements can leave footprints within the interior of the genome that document previous telomere breakage events. The purpose of this study was to examine MoTeR relics within 10 genomes of strains of M. oryzae to document telomere instability among strain lineages, as well as to uncover MoTeR relic distribution, shared evolutionary history, and associated genome rearrangements. A series of local BLASTn and grep searches in the Unix Command Line were used to find and describe MoTeR relics. We found that MoTeR relics were found, on average, within 250 kb of the telomere and were often flanked by duplicate sequences that also mapped closely to telomeres. Our initial hypothesis for this study that MoTeR relics would largely represent unique strain or lineage-specific rearrangements was neither unequivocally supported nor entirely refuted. Intergenomic comparisons of MoTeR relics revealed several regions of shared synteny among distantly related strains that points towards their existence within ancestral strains, as well as seemingly strain- and lineage-specific relics that may be the result of more recent rearrangements. MoTeR relics serve as markers for investigating telomere dynamics in M. oryzae and further study might elucidate whether telomere instability within M. oryzae might play an adaptive potential in being able to quickly evolve and spread into new host plants as well as overcome resistance in others.

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