What does a DNA microarray measure?

What does a DNA microarray measure?

• A. DNA sequence of a single gene.
• B. Protein abundance in a sample.
• C. Expression levels of thousands of genes simultaneously.
• D. Chromosome copy number.

Answer: (C)

DNA microarrays are used to measure transcript abundance across thousands of genes at once. A chip contains many DNA probes for different genes, and RNA from a sample is converted to labeled cDNA that hybridizes to those probes. The fluorescence at each spot reflects how much of that gene’s transcript is present, giving a readout of gene expression levels on a genome-wide scale. This is why the best choice describes expression levels of thousands of genes simultaneously. It’s not about sequencing the DNA of a single gene, nor about counting proteins in a sample, nor about determining chromosome copy number (that uses different array approaches).

DNA microarrays are used to measure transcript abundance across thousands of genes at once. A chip contains many DNA probes for different genes, and RNA from a sample is converted to labeled cDNA that hybridizes to those probes. The fluorescence at each spot reflects how much of that gene’s transcript is present, giving a readout of gene expression levels on a genome-wide scale. This is why the best choice describes expression levels of thousands of genes simultaneously. It’s not about sequencing the DNA of a single gene, nor about counting proteins in a sample, nor about determining chromosome copy number (that uses different array approaches).