Question

A DNA Microarray or ‘gene-chip’ consists of:

• A. A single-stranded DNA sample attached to the microarray surface and fluorescent labelled RNA probes
• B. An RNA probe attached to the microarray surface and fluorescent labelled DNA samples
• C. An RNA sample attached to the microarray surface and fluorescent labelled RNA probes
• D. A single-stranded DNA probe attached to the microarray surface and fluorescent labelled single-stranded cDNA samples

Answer 1

The correct option is D A single-stranded DNA probe attached to the microarray surface and fluorescent labelled single-stranded cDNA samples

A gene chip or a microarray consists of synthesized probes of the DNA sequence of the gene to be studied. RNA of the gene whose expression we are studying is isolated and converted to fluorescently labelled cDNA known as the gene sample. The hybridization of the sample with the probe produces fluorescence which is picked up by a specialized CCD camera. The more the fluorescence, more is the activity of the gene in the cell and vice versa.