Date of Award

1-2023

Document Type

Thesis

Degree Name

Master of Science in Biology

Department

Biology

First Reader/Committee Chair

Lua Lopez-Perez

Abstract

Transcriptomics is a modern technique in genomics that utilizes RNA sequences to get a snapshot of genetic expression. This is a powerful tool in non-model species lacking a reference genome. Thus, the application of comparative transcriptomics has the potential to help us elucidate the evolutionary mechanisms that facilitate species invasion. Carpobrotus edulis is a prolific and widespread invasive succulent plant belonging to the Aizoaceae family. A native to South Africa, this species has become a dominant invader of many Mediterranean coastal areas. In this study, we leveraged the use of RNAseq to investigate evolutionary changes among invasive populations. RNA-seq data was gathered from experimental native and invasive populations tested under stress conditions and used to assemble a de novo transcriptome and perform a differential expression analysis. We provide the first annotated transcriptome for the plant genus Carpobrotus and the Aizoaceae family. Differential expression analysis identified several differentially expressed transcripts between native and invasive populations. Invasive populations showed no increases in putative genes related to flowering and decreased expression in genes related to protection and defense. Supporting the hypothesis that C. edulis has undergone significant genetic modification in the invaded range. These results are expected under the Evolution of Increased Competitive Ability hypothesis and Genetic Accommodation hypothesis, wherein novel metabolic processes and changes in gene regulatory networks evolve when introduced to ecologies.

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