RNA-Seq vs Microarray: Key Differences & When to Choose Each
RNA-Seq counts individual RNA molecules with next-generation sequencing; Microarray measures fluorescence of fixed probes bound to cDNA fragments.
Researchers grab either name when they need gene-expression data, but grants, timelines, and sample quality quietly pick the tool for them—confusing the decision long before the lab bench.
Key Differences
RNA-Seq delivers single-base resolution, novel transcripts, and digital counts across >10⁶ dynamic range. Microarray offers lower cost, established pipelines, and limited to known genes with ~10²-fold range, often within 24 hours.
Which One Should You Choose?
Choose RNA-Seq for discovery, low input, or splice-variant work. Pick Microarray for well-annotated genomes, large clinical cohorts, or tight budgets where quick turnaround outweighs depth.
Examples and Daily Life
Cancer labs sequence FFPE tumors with RNA-Seq to spot rare fusions, while pharma screens drug signatures on 500 arrays in a week to cut costs.
Can I start with Microarray and switch later?
Yes; archive extra RNA, but batch effects may limit direct merging—plan normalization ahead.
Does single-cell need RNA-Seq?
Almost always; picogram RNA levels exceed Microarray sensitivity, making sequencing the default.