30. Which is best technique to separate the two loci on chromosome?
(1) C- banding (2) Gel electrophoresis
(3) G-banding (4) Chromatography
The best technique to separate or differentiate two loci on a chromosome is G-banding (option 3).
Explanation of Options
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C-banding: This technique stains constitutive heterochromatin, primarily centromeric regions of chromosomes, by using a specific Giemsa staining after denaturation. It strongly highlights the centromere and some heterochromatin blocks but does not provide detailed banding patterns along the chromosome arms, limiting its ability to distinguish closely linked loci except around centromeric heterochromatin.
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Gel electrophoresis: This method separates DNA fragments based on size but is not a cytogenetic technique for visualizing chromosome structure or location of loci. Gel electrophoresis is widely used in molecular biology for DNA/RNA/protein fragment analysis but cannot map loci directly on chromosomes physically.
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G-banding: The most commonly used technique in cytogenetics, G-banding involves treating chromosomes with trypsin followed by Giemsa staining. It creates a reproducible pattern of light and dark bands along the lengths of chromosomes by preferentially staining AT-rich regions more darkly. This detailed banding pattern allows physical localization and differentiation of specific loci along chromosome arms, making it ideal for separating and identifying loci.
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Chromatography: A biochemical method mainly for separating molecules in mixtures based on physical or chemical properties. It is unrelated to chromosome banding or cytogenetic locus separation and therefore not appropriate for this purpose.
Introduction:
Separating and identifying exact locations of loci on chromosomes is crucial in genetics and cytogenetics for understanding gene structure and chromosomal abnormalities. Multiple techniques exist, but the most effective method to separate two loci on a chromosome is G-banding. This article explains why G-banding stands out compared to other methods like C-banding, gel electrophoresis, and chromatography.
This explanation and SEO structure should help in content creation for educational or research platforms on chromosome separation techniques, emphasizing G-banding’s role in locus differentiation with clarity and accuracy.
