Flow Cytometry and Its Utility

Flow cytometry is a laser-based biophysical technique to study optical properties of microscopic particles in fluid suspension. The technology is not only routinely used in medicine (transplantation, hematology, cancer, prenatal diagnosis, genetics, and sperm sorting for sex preselection) but also has many other applications in basic research, crop improvement, clinical practice, and clinical trials. The principles of flow cytometric chromosome analysis and sorting known as flow cytogenetics and research in this field have increased over the past four decades due to high sensitivity and precision of this technique. The use of nucleic acid-specific fluorochromes has semiautomated quantitative chromosome analysis, thus reducing subjectivity of preexisting slide-based methods. Flow cytometric classification of chromosomes (flow karyotyping) enables detection of chromosomal aberrations, while flow sorting permits isolation of single chromosome types in large quantities to be used for gene mapping, preparation of chromosome-specific gene libraries, and ultimately sequencing leading to chromosome genomics. Flow fluorescent in situ hybridization (FISH), i.e., combined fluorescent in situ hybridization in suspension (FISHIS) and flow cytometry using microsatellite DNA or gene-specific probes, is another approach to increase our knowledge on structure, function, and evolution of chromosomes. These techniques provide increased value for diagnosis and management of clinical diseases, especially cancer which is generally characterized by high chromosomal instability. Flow cytogenetics also has important applications in plant biology, especially in the study of genome evolution and crop improvement. This review outlines the utility of flow cytometry in chromosomal analysis, its applications, limitations, and future directions.