Cytogenetic analysis forms an essential part of characterizing and identifying cell lines, in particular those established from tumors. In addition, karyotypic analysis can be used to distinguish individual subclones and to monitor stability. This chapter describes basic cytogenetic procedures suited to cells in continuous culture. The provision of unlimited material by cell lines encourages an heuristic approach to harvesting and hypotonic treatments to yield metaphase chromosome slide preparations of improved quality suitable for subsequent banding and fluorescencein situhybridization (FISH) analysis. The experience of the writers with more than 500 different cell lines has shown that no single hypotonic harvesting protocol is adequate to consistently deliver satisfactory chromosome preparations. Thus, evidence-based protocols are described for hypotonic harvesting, rapid G-banding, and FISH analysis of cell cultures to allow troubleshooting and fine-tuning to suit the requirements of individual cell lines.
