Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

David Smith

Abstract

A large amount of diversity in genomic size and content exists within the mitochondrial and plastid genomes of green algae. However, there are still many un-sequenced green algal organelle genomes. In Smith et al. 2010, the green algal species Dunaliella salina, isolated from Western Australia (strain CCAP 19/18), had its organelle genomes fully sequenced. The genomes of this organism were found to contain large amounts of noncoding DNA. The lack of sequenced organelle genomes of green algae prevented the comparison of genomic architectures in other closely related species. In this study, I expanded on the information from the 2010 study by sequencing the organelle genomes from two Dunaliella species (D. salina CONC-001 and D. viridis CONC-002) isolated from a saline pond in Chile and compared their genomic architectures to that of D. salina CCAP 19/18. Sequencing, assembly, and bioinformatics analyses of the Chilean strains revealed genomic expansion within their mitochondrial and plastid genomes. Accompanying the increase in organelle genome size were highly inflated noncoding regions and an excess of introns. Upon further investigation, D. salina CCAP 19/18 and D. salina CONC-001 were found to be more similar to each other than to D. viridis CONC-002. Nevertheless, the two D. salina strains, given their major differences in organelle genome size, appear to represent distinct species.


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