The technique used to locate specific genes in chromosomes is
The technique used to locate specific genes in chromosomes is
Select an option to attempt
Correct Answer: Option B
Explanation
Fluorescence In Situ Hybridisation (FISH): a cytogenetic technique for localising specific nucleic acid sequences within fixed cells or on chromosomes. Procedure: (1) Prepare fluorescently labelled DNA probe (complementary to target gene sequence); (2) Denature chromosomal DNA in metaphase spread; (3) Hybridise labelled probe to complementary chromosomal sequences; (4) Detect hybridisation signals by fluorescence microscopy. The fluorescent signal appears at the chromosomal location of the target gene. Multicolour FISH (m-FISH, spectral karyotyping) simultaneously paints all 24 human chromosomes in different colours. FISH is used for: chromosomal rearrangements, gene copy number, translocations, deletions, amplifications, gene mapping. Southern blotting detects DNA sequences in gel; Western detects proteins; colony hybridisation detects plasmid inserts; PCR amplifies sequences but doesn't localise them on chromosomes.