Microarray introduction
Fri, Oct 30, 2026 · Week 10 · Genetics of Disease (Medical Interventions)
Today's goal: Explain how a microarray uses hybridization to test many genes at once and where it differs from PCR.
What a finished product looks like
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Hybridization in my words: A microarray is covered with single-stranded probe sequences. A labeled sample of DNA or cDNA washes over it, and each piece sticks (hybridizes) only where it finds its complementary probe. A bright, colored spot means that gene's sequence was present in the sample; a dark spot means it was not.
Method comparison: I compared PCR, gel, and microarray by what each is best for.
Microarray limit not shared by the others: A microarray needs specialized scanning equipment and bioinformatics software to read thousands of spots, while a PCR product or a gel can be set up and read with much simpler tools.
| Method | Best for | Output |
|---|---|---|
| PCR | Amplifying one target sequence | Many copies of one region |
| Gel | Separating fragments by size | Bands showing fragment sizes |
| Microarray | Surveying thousands of genes at once | Spot pattern showing expression |
Also due today: Submit your comparison table to the course shell.
WebXam problem for today's skill
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.