Question

Which one of the below statements is not true with respect to DNA microarray?

• A. DNA microarrays comprise known DNA sequences spotted on a small chip
• B. Genome wide transcription analysis can be performed using this technology
• C. Arrays can be designed and used for genome wide genotyping single nucleotide polymorphism
• D. Array comparative genomic hybridization cannot be used to detect copy number changes in any DNA sequence between two samples.

Hint:

Remember that Array CGH is widely used in clinical diagnostics to detect copy-number variations (insertions/deletions) associated with genetic disorders.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
DNA microarray is a high-throughput hybridization technology used to analyze the expression, presence, or structure of thousands of genes simultaneously.

Step 2: Detailed Explanation:
- (A) is true because microarrays consist of thousands of microscopic spots of known, single-stranded DNA probe sequences attached to a solid surface (chip).
- (B) is true because labeling and hybridizing total cellular cDNA allows for the simultaneous analysis of transcription levels across the entire genome.
- (C) is true because high-density oligonucleotide arrays can be designed to detect single nucleotide polymorphisms (SNPs) across a genome.
- (D) is false because Array Comparative Genomic Hybridization (aCGH) is a standard technique used to detect and locate copy number variations (CNVs), insertions, and deletions by comparing genomic DNA from two different samples.
Therefore, stating that aCGH cannot be used for this purpose is incorrect.

Step 3: Final Answer:
The incorrect statement is (D), as aCGH is designed to detect copy number changes.