Which fluorescent method is used to detect chromosome abnormalities using DNA probes?
Fluorescence In Situ Hybridization combines cytogenetics with fluorescence detection. Denatured metaphase chromosomes or interphase nuclei are hybridized with fluorescently labeled locus-specific, centromeric, or whole-chromosome painting probes. Upon specific binding, signals are visualized by fluorescence microscopy, allowing detection of aneuploidies, deletions, duplications, translocations, and amplifications. Unlike SAGE or CGH, FISH preserves cellular morphology and provides single-cell resolution. Comparative genomic hybridization assesses copy number changes but not balanced rearrangements with the same morphological precision afforded by probe-based in situ labeling and visualization.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.