نبذه عن الكتاب: Molecular Cytogenetics in Medicine An Overview Yao-Shan Fan 1. Introduction The word “chromosome” was introduced over a century ago from the Greek language meaning “colored body.” While cytogenetics refers to the study of chromosomes, the term molecular cytogenetics is used to describe the analysis of genomic alterations using mainly in situ hybridization based technology. Fluorescent in situ hybridization (FISH) was initially developed in the late 1980s from radioactive hybridization procedures used for mapping human genes (1–4). Soon, this technology was utilized for the characterization of chromosomal rearrangements and marker chromosomes (5,6), the detection of microdeletions (7), and the prenatal diagnosis of common aneuploidies (8,9) in clinical cytogenetics laboratories. At the same time, numerous DNA probes have been commercialized, further promoting the wide-spread clinical applications of molecular cytogenetics. Many new FISH techniques have been developed, including primed in situ labeling (PRINS [10]), fiber FISH (11,12), comparative genomic hybridization (CGH) (13), chromosome microdissection (14,15), spectral karyotyping (SKY [16]), Multiple color FISH (M-FISH [17,18]), color banding (19), FISH with multiple subtelomeric probes (20), and arraybased CGH (21,22). With the current FISH techniques, deletion or rearrangement of a single gene can be detected, cryptic chromosome translocations can be visualized, the copy number of oncogenes amplified in tumor cells can be assessed, and very complex rearrangements can be fully characterized. Using interphase FISH, genomic alterations can be studied in virtually all types of human tissues at any stage of cell division, without the need of cell culture and chromosome preparation. The development of FISH technology in the past two decades has brought cytogenetics into the molecular era, and made the “colored bodies” more colorful and brighter.