Graduate Program

Biological Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

Summer 2020

Thesis Director

Yordan S. Yordanov

Thesis Committee Member

Gary A. Bulla

Thesis Committee Member

Elena Yordanova


Poplars have become one of the most frequently studied plant species for their applications in biotechnology, commercial benefits, and ecological importance. Microarray analysis is commonly used to analyze differential gene expression in many organisms. Investigations have examined differential gene expression and performed functional analyses on a single tissue or organ within poplar trees or a closely related set of tissues and organs, but usually do not broadly analyze gene expression across a large number of tissues and organs in poplar. This thesis work aims to generate data on the most differentially expressed genes for the major groups of tissues and organs of poplar and analyze the results with comparison to prior studies. Publicly available expression value files were normalized and analyzed using established methods for identification of differentially expressed genes. Then, a stringent selection of statistical tests including correlation analysis was used to identify genes highly expressed in each tissue and organ group and compare findings with the results of prior related investigations. This method identified thousands of tissue-enriched genes for each of the tissue/organ groups analyzed, with the root and seedling groups showing the highest numbers and the bark and phloem groups with the lowest. Importantly, we also identified ten genes in each group that were highly specific for that tissue, although the function of many of these genes is not yet known.

Available for download on Saturday, August 20, 2022