Question

Which technique is not used for the analysis of hybrid cells formed by the fusion of two unrelated protoplasts?

• A. Fluorescence in situ hybridization
• B. Northern blotting
• C. Isozyme analysis
• D. RFLP

Hint:

To prove a hybrid is a hybrid, you must check its "ID Card" (DNA/Chromosomes) or its "Signature" (Proteins/Isozymes). Northern Blotting only checks the "Message" (RNA), which isn't an ID.

Answer 1

The Correct Option is B

Concept: After protoplast fusion, researchers must confirm if the resulting cells are true hybrids (containing genetic material from both parents). This requires tools that can distinguish between the DNA or the stable protein markers of the two parental species.

Step 1: Tools for DNA/Chromosomal Analysis.
Fluorescence in situ hybridization (FISH) (1) allows researchers to see the physical presence of chromosomes from both parents. RFLP (4) (Restriction Fragment Length Polymorphism) is a DNA-based marker technique used to identify the presence of both parental genomes at the molecular level.

Step 2: Tools for Protein Analysis.
Isozyme analysis (3) looks at different forms of the same enzyme. Since different species often have unique isozyme patterns, a hybrid cell will show a "combined" pattern of bands, confirming its hybrid nature.

Step 3: The Role of Northern Blotting.
Northern blotting (2) is used to study gene expression (RNA levels). While it tells you which genes are "turned on," it is not a standard or reliable tool for verifying the genomic identity or origin of a hybrid cell, as gene expression can vary wildly due to environmental factors rather than just heritage.