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How do microarrays show which genes are active at a particular developmental stage?
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bioinformatics
This computerized image of anthrax shows the various structural relationships of seven units within the protein and demonstrates the interaction of a drug (shown in yellow) bound to the protein to block the so-called lethal factor unit. Bioinformatics plays an important role in enabling scientists to predict where a drug molecule will bind within a protein, given the individual structures of the molecules.
Microarrays are powerful tools used in functional genomics to identify the "transcriptome"—the complete set of messenger RNA (mRNA) transcripts produced by an organism at a specific developmental stage.1
To determine which genes are active, the process generally follows these steps:
- Preparation: mRNA is extracted from a sample taken at the desired developmental stage. This mRNA is often converted into complementary DNA (cDNA) or labeled directly with a fluorescent dye.21
- Hybridization: The labeled sample is applied to a microarray chip, which contains thousands of ordered DNA probes, each representing a specific gene.21
- Detection: Molecules in the sample bind (hybridize) to their corresponding gene probes on the chip. After washing away unbound material, the chip is scanned using laser-based technology to detect fluorescence.2
- Analysis: The resulting fluorescent spots indicate which genes were expressed. By comparing these signals, researchers can define the transcriptome and assess gene activity levels across different developmental stages or conditions.21