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John Henry McCusker

Associate Professor Emeritus of Molecular Genetics and Microbiology
Molecular Genetics and Microbiology
Duke Box 3020, Durham, NC 27710
239 Jones Bldg, Dept of Molecular Genetics & Microbiolo, Durham, NC 27710

Overview


My research uses whole genome analysis as well as standard genetic and molecular biological techniques in S. cerevisiae and, in particular, applies these techniques to the following areas:
The development of S. cerevisiae as a microbial model for quantitative genetics. Quantitative traits are extremely important and have been extensively studied in higher eukaryotes. Unfortunately, our understanding of quantitative traits is poor because of: the polygenic and additive nature of quantitative trait loci; the complexity of the structures and processes affected by quantitative traits in higher eukaryotes; and, the large genome size and genetic intractability (compared to microorganisms) of high eukaryotes. The simplicity and genetic tractability of S. cerevisiae will alllow us to define quantitative traits in precise genetic and molecular terms. This analysis will aid our understanding of quantitative traits in higher eukaryotes.
The development of S. cerevisiae as a model for the pathogenic fungi. Our knowledge of fungal pathogenesis has been hampered by the genetic intractability of the pathogenic fungi. I have discovered pathogenic variants of S. cerevisiae and have shown that these strains have properties typical of other pathogenic fungi, such as the ability to grow at very high temperatures and a novel phase variation switching system. S. cerevisiae is a close relative of many of the pathogenic fungi and, as we have shown, is an emerging opportunistic pathogen which is virulent in mouse model systems. Genetic analysis of S. cerevisiae pathogenesis and virulence will be applied to more common pathogenic fungi, such as Candida albicans.
The study of phase variation in s. cerevisiae as a model for phase variation (or colony morphology switching) in pathogenic fungi. Phase variants are genetically heritable gene expression states. S. cerevisiae phase variation is also a model for cellular differentiation and gene regulation in higher eukaryotes.

Current Appointments & Affiliations


Associate Professor Emeritus of Molecular Genetics and Microbiology · 2022 - Present Molecular Genetics and Microbiology, Basic Science Departments

Recent Publications


RNA viruses, M satellites, chromosomal killer genes, and killer/nonkiller phenotypes in the 100-genomes S. cerevisiae strains.

Journal Article G3 (Bethesda) · September 30, 2023 We characterized previously identified RNA viruses (L-A, L-BC, 20S, and 23S), L-A-dependent M satellites (M1, M2, M28, and Mlus), and M satellite-dependent killer phenotypes in the Saccharomyces cerevisiae 100-genomes genetic resource population. L-BC was ... Full text Link to item Cite

A novel narnavirus is widespread in Saccharomyces cerevisiae and impacts multiple host phenotypes.

Journal Article G3 (Bethesda) · February 9, 2023 RNA viruses are a widespread, biologically diverse group that includes the narnaviridiae, a family of unencapsidated RNA viruses containing a single ORF that encodes an RNA-dependent RNA polymerase. In the yeast Saccharomyces cerevisiae, the 20S and 23S RN ... Full text Link to item Cite

Mitochondrial Genome Variation Affects Multiple Respiration and Nonrespiration Phenotypes in Saccharomyces cerevisiae.

Journal Article Genetics · February 2019 Mitochondrial genome variation and its effects on phenotypes have been widely analyzed in higher eukaryotes but less so in the model eukaryote Saccharomyces cerevisiae Here, we describe mitochondrial genome variation in 96 diverse S. cerevisiae strains and ... Full text Link to item Cite
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Recent Grants


Nucleo-Mitochondrial quantitative traits in S. cerevisiae

ResearchPrincipal Investigator · Awarded by National Institutes of Health · 2017 - 2022

Genetics Training Grant

Inst. Training Prgm or CMEMentor · Awarded by National Institutes of Health · 1979 - 2020

Organization and Function of Cellular Structure

Inst. Training Prgm or CMEMentor · Awarded by National Institutes of Health · 1975 - 2020

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Education, Training & Certifications


Brandeis University · 1987 Ph.D.