102. Which among the following techniques does NOT depend on nucleic acid hybridization?
1. DNA microarray
2. Chromatin Immunoprecipitation
3. Chromosome painting
4. Southern blotting

Correct Answer:

2. Chromatin Immunoprecipitation

Explanation:

Here’s a breakdown of each technique:

1. DNA Microarray:
   DNA microarrays involve nucleic acid hybridization. In this technique, labeled cDNA or RNA samples are hybridized to specific probes on a chip to measure gene expression or detect mutations.

2. Chromatin Immunoprecipitation (ChIP):
   Chromatin Immunoprecipitation does not rely on nucleic acid hybridization. Instead, it is a technique used to investigate the interaction between proteins and DNA in the cell. ChIP involves using antibodies to pull down proteins that are bound to DNA, followed by sequencing or PCR to identify the DNA regions associated with the protein of interest.

3. Chromosome Painting:
   Chromosome painting involves fluorescently labeled DNA probes that hybridize to specific chromosome regions, allowing visualization of chromosomal structures. Thus, it depends on nucleic acid hybridization.

4. Southern Blotting:
   Southern blotting is a classic technique that uses nucleic acid hybridization. It involves transferring DNA from a gel to a membrane and using labeled probes to detect specific sequences within the DNA.

Conclusion:

Chromatin Immunoprecipitation (ChIP) is the technique that does not depend on nucleic acid hybridization, as it focuses on protein-DNA interactions rather than hybridizing DNA with complementary probes.

Correct Answer: 2. Chromatin Immunoprecipitation