First Name:
Rachel
Last Name:
Gooding
Major Department:
Biology
Thesis Director:
Mary Connell
Date of Thesis:
May 2011
The marine brown alga Scytosiphon lomentaria undergoes a photoperiod-mediated morphological transition from a basal system microthallus in the long days of summer to the addition of reproductive macrothalli in the short days of winter, but little is known concerning the gene regulation of this metamorphosis. This research focuses on using molecular techniques to identify those specific genes that are differentially expressed in S. lomentaria during short-day and long-day photoperiods and induce the alga's growth of macrothalli in the winter. Putative differentially expressed bands of cDNA were PCR amplified and analyzed through sequencing and the use of BLAST database tools to identify gene function. The relative gene expression levels of these sequences were measured through use of quantitative Real-Time PCR (qRT-PCR). Of the initial 1560 putative differentially expressed bands collected during the 2009 graduate work of Adam Dale Miller, 32 bands were successfully PCR amplified in this project, 20 of which were successfully cloned, and 18 clones were successfully sequenced. Of these 18 sequenced transcripts, 6 were found to have highly similar sequences to known genes in the NCBI and BOGAS databases and 3 were found to be putative hypothetical proteins or proteins of unknown function. The relative gene expression of 6 of the 18 sequences was measured with qRT-PCR, and the up-regulation of 2 sequenced transcripts during short-day photoperiods was confirmed. Through investigation of the identities and relative transcription levels of genes during different day lengths, this study adds to our understanding of S. lomentaria's genome and the role of differential gene expression in inducing this alga's photoperiodic morphogenesis.