Document Type

Thesis

Date of Degree

Spring 2009

Degree Name

MS (Master of Science)

Degree In

Biology

First Advisor

Debashish Bhattacharya

Abstract

Transposable elements (TEs) are acknowledged sources of genetic change within organisms. The effects of transposition can range from the disruption or creation of a single gene to large-scale genome rearrangements. Transposition events can result in beneficial mutations which allow an organism to adapt to a new environment. In the last three years, several studies have reported that some miRNAs, small RNAs involved in post-transcriptional gene regulation, have evolved from TEs. miRNAs play an important role in the stress responses of many organisms. Interestingly, TEs are derepressed under the same stress conditions that miRNAs are known to ameliorate. The observation that miRNAs are known to evolve from TEs and that TEs are derepressed under stress conditions lead me to question whether TEs play a role in environmental adaptation through the creation of small RNA networks. To test this idea, Chlamydomonas reinhardtii cultures were grown under low carbon, nitrate enriched conditions and the small RNA pool was analyzed. I found that these conditions do stimulate the expression of novel small RNAs and that some of these RNAs and their targets are derived from transposition events.

Keywords

Chlamydomonas, low CO2, miRNA, nitrate, Transposable elements

Pages

vii, 37 pages

Bibliography

Includes bibliographical references (pages 34-37).

Copyright

Copyright 2009 Heather Marie Tyra

Included in

Biology Commons

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