Which technology can profile gene expression across thousands of genes at once?

Which technology can profile gene expression across thousands of genes at once?

• A. Microarray technology.
• B. Sanger sequencing.
• C. Gel electrophoresis.
• D. Western blotting.

Answer: (A)

Profiling gene expression across thousands of genes at once requires a platform that can measure many transcripts in parallel. A DNA microarray places thousands of DNA probes on a single chip that correspond to different genes. RNA from a sample is converted to labeled cDNA, which is then allowed to hybridize to the array. The amount of labeled cDNA that binds at each spot is detected by fluorescence and corresponds to how strongly that gene is expressed in the sample. By scanning the entire array, you get a comprehensive expression profile for thousands of genes simultaneously, and you can compare profiles under different conditions or treatments. Other techniques don’t offer this broad, parallel readout. Sanger sequencing sequences individual DNA fragments, not thousands of transcripts at once. Gel electrophoresis separates fragments by size and is used for analysis of a few targets or fragment sizes rather than genome-wide expression. Western blotting detects specific proteins and is typically limited to a smaller set of targets, not thousands of gene transcripts.

Profiling gene expression across thousands of genes at once requires a platform that can measure many transcripts in parallel. A DNA microarray places thousands of DNA probes on a single chip that correspond to different genes. RNA from a sample is converted to labeled cDNA, which is then allowed to hybridize to the array. The amount of labeled cDNA that binds at each spot is detected by fluorescence and corresponds to how strongly that gene is expressed in the sample. By scanning the entire array, you get a comprehensive expression profile for thousands of genes simultaneously, and you can compare profiles under different conditions or treatments.

Other techniques don’t offer this broad, parallel readout. Sanger sequencing sequences individual DNA fragments, not thousands of transcripts at once. Gel electrophoresis separates fragments by size and is used for analysis of a few targets or fragment sizes rather than genome-wide expression. Western blotting detects specific proteins and is typically limited to a smaller set of targets, not thousands of gene transcripts.