The Chromosome Transmission Fidelity Assay for Measuring Chromosome Loss in Yeast

: The budding yeast Saccharomyces cerevisiae has served as an excellent model system for studying highly conserved biological pathways including pathways involved in genome transmission and maintenance. The Chromosome Transmission Fidelity (CTF) colony color assay was developed to assess chromosome instability (CIN) in yeast, by monitoring the loss or gain during cell division of an artificial chromosome fragment carrying a visual marker. The CTF assay monitors changes in chromosome number, allowing the detection of mutants that exhibit increased rates of chromosome nondisjunction or chromosome loss. In this article, we describe the SUP11-marker-based CTF assay system, and the methodologies for both qualitative analysis of mutants affecting chromosome transmission, and quantitative analysis for determining the types and rates of errors in chromosome transmission using half-sector analysis.