Award Date

May 2017

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Life Sciences

First Committee Member

Philippos Tsourkas

Second Committee Member

Allen Gibbs

Third Committee Member

Mira Han

Fourth Committee Member

Kaushik Ghosh

Number of Pages

73

Abstract

Drosophila melanogaster selected for resistance to desiccation (no food or water) display slower development and a higher body mass compared to fed controls due to an extended third larval instar. I hypothesize that desiccation selected D. melanogaster larvae will have a different gene expression profile compared to fed controls. Separate populations of D. melanogaster were subjected to desiccation (no food or water), starvation (no food) until 80-85% mortality, for 75 generations. mRNA from the larval fat body was collected at 88 hours, 96 hours, 112 hours and 120 hours post-hatching. Four replicate samples were used for each condition and time point. Gene expression was measured using two color cDNA microarrays. I analyzed the microarray data using a two-way factorial design ANOVA implemented in R using a significance level of 0.05 with FDR correction. The FDR adjusted results showed 43 genes differentially expressed for selection condition, 4590 genes for time, and 122 for selection by time (interaction). I then used DAVID 6.7 to explore which biological pathways are over-represented for these genes. One biological process was shown to be over-represented for the selection genes, 67 for time, and 10 for interaction. These over-represented processes suggest desiccation selected and control populations are indeed developing differently.

Keywords

desiccation selection; differential gene expression; Drosophila melanogaster; larval fat body

Disciplines

Biology | Genetics

Language

English


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