The role of the Giemsa stain in cytogenetics

In just half a century since the human diploid chromosome number was correctly identified as 46, there has been a rapid expansion in our understanding of both the genetic foundation of normal human development and the development of various constitutional and acquired abnormalities. The ability to detect numerical and structural chromosomal abnormalities was made possible by the Giemsa stain. Despite the recent advent of powerful molecular-based cytogenetic techniques (e.g., fluorescence in situ hybridization, array-based comparative genomic hybridization), Giemsa-based chromosomal banding and staining techniques retain their crucial role in cytogenetics.