Final answer:
Fluorescent in situ hybridization (FISH) is used to locate specific DNA sequences within the cell nucleus, utilizing a fluorescent dye-labeled DNA probe that hybridizes with its matching DNA sequence in the sample.
Step-by-step explanation:
Fluorescent in situ hybridization (FISH) is a molecular cytogenetic technique that allows researchers to detect and locate specific DNA sequences on chromosomes within a cell. During the FISH process, a sample's DNA must be denatured, converting it to single-stranded form so that a complementary fluorescently labelled DNA probe can anneal (hybridize) to the chromosomal DNA at the point where both sequences match. This method is particularly useful in identifying the position of particular chromosomes or specific DNA sequences within the cell nucleus (option C).
The probe, which is a short fragment of DNA, is tagged with a fluorescent dye and bathed over the membrane or slide containing the DNA to be tested. This tagged probe binds (hybridizes) with the complementary DNA sequence present in the sample. Following hybridization, the fluorescence signals can be visualized under a microscope, providing a visual representation of the probe's location on the chromosomes.
FISH is highly useful for analyzing the structural and numerical chromosome abnormali
ties, diagnosing certain diseases, detecting extrachromosomal genes, and can play a critical role in genetic research and medical diagnostics.