Diverse yeasts hold massive potential for research and industrial applications; however,they are underutilized by the field of microbiology due in part to the lack of genetic tools available to researchers. The majority of researchers utilize thoroughly characterized model yeasts, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe, and industry scientists often focus on the former for its ease of culturing, genetic modification, and fermentative capacity. Despite this, only a subset of strains are commonly used, including laboratory strains for research and heavily domesticated strains for applications in producing bread, fermented beverages, and bioethanol. Additionally, brewers and some yeast distributors lack the tools for characterizing and predicting phenotypes for specialized brewing strains, such as diastatic yeast, limiting their usability. Diastatic yeast strains, in particular, are of heightened interest for industrial applicationsdue to their ability to breakdown complex polysaccharides as a precursor for fermentation by the extracellular-glucoamylase-encoding STA1-3 genes. These strains can be utilized to make distinct beer styles or can be harnessed to breakdown dextrin-rich substrates for bioethanol production. However, for cases in which these strains are unintentionally or improperly used, they can cause product defects and are considered a spoilage organism. In this work, I sought to expand the genetic toolkit available to researchers who study diverse yeasts and utilized these plasmids to characterize a panel of diastatic brewing strains. First, I constructed and tested a series of drug-selectable plasmid shuttle vectors for applications in diverse yeasts. In doing so, I introduced 18 plasmids which can be maintained across distinct yeast genera, including Lachancea, Metschnikowia, Pichia, Saccharomyces, and Torulaspora. These plasmids also contained gene expression systems which were successfully utilized by various species and strains within the Saccharomyces and Torulaspora genera, showcasing their broad applicability. Next, I utilized these plasmids, in addition to high-quality genomic data, to characterize STA1-3 open reading frame and promoter variants from diastatic brewing yeast. In addition to characterizing diastatic function in relation to genotypic variations, I utilized phylogenetic approaches to propose a conceptual model for the evolutionary history of the STA gene family, expanding our knowledge of diastatic strains altogether.