Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Jeffrey Lewis

Committee Member

Mack Ivey

Second Committee Member

Michael McCoy

Third Committee Member

Kate Chapman

Abstract

Transformation, a type of horizontal gene transfer, describes the uptake, maintenance, and integration of environmental DNA by cells. Despite the known effects of transformation on evolutionary processes, little is known about the genetic basis of this phenomenon. Saccharomyces cerevisiae is a eukaryote able to transform at quantifiable rates when made chemically competent and treated with a heat shock. S. cerevisiae also has variation in transformation efficiencies between various strains, and high recombination rates allow for sufficient allele “shuffling” in intercross populations. This project utilizes a bulk segregant analysis approach to compare sequencing data between transformant pools and non-transformant pools of intercross populations (created with a transformation-efficient parental strain and a transformation-inefficient parental strain). Significance tests revealed heightened variation along chromosome IV in the YPS x YJM627 (wild-wild cross). This work indicates the role of variants, many of which were found on chromosome IV, in conferring transformation efficiency and highlights several candidate causal genes. Significance tests revealed many slightly statistically elevated regions in the S288C x Y10 (lab-wild) cross across the genome, signaling that heightened transformation efficiency in S288C is a genetically complex trait, and may be driven by polygenic factors. Both crosses provide interesting insight into the genomic factors driving variation in transformation efficiency in S. cerevisiae. 

Keywords

transformation, transformation efficiency, bulk segregant analysis, saccharomyces cerevisiae

Download

Share

COinS