American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

Which method is commonly used to visualize chromosomal abnormalities in cytogenetics?

1. Southern blotting

2. Fluorescence in situ hybridization (FISH)

3. Polymerase chain reaction (PCR)

4. Western blotting

The correct answer is: Fluorescence in situ hybridization (FISH)

Fluorescence in situ hybridization (FISH) is a powerful and commonly used method in cytogenetics for visualizing chromosomal abnormalities. FISH employs fluorescently labeled DNA probes that bind to specific regions on chromosomes, allowing for the detection of changes in chromosome number, structure, or location of specific genes. This technique enables researchers and clinicians to identify chromosomal abnormalities such as deletions, duplications, translocations, and aneuploidies directly in interphase or metaphase cells. The advantages of FISH include its ability to provide real-time results, high sensitivity, and specificity. It can be utilized across various conditions, such as cancer diagnostics, prenatal testing, and identifying genetic syndromes, making it an essential tool in the field of cytogenetics. Other methods mentioned, like Southern blotting or Western blotting, are primarily used for detecting DNA and proteins, respectively, and do not provide direct visualization of chromosomal structures. Polymerase chain reaction (PCR) is designed to amplify specific segments of DNA but is not suited for visualizing whole chromosomes or chromosomal abnormalities. Thus, FISH stands out as the method specifically tailored for this purpose in cytogenetics.