Difference between DNA microarray and RNA microarray

Question

[ebrudermanver]

What is the technological differences between the DNA microarray and RNA microarray, specifically when gene expression is measured by each? Wikipedia says "Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome.". RNA microarray also can be used to measure the expression levels of large numbers of genes simultaneously, I think. So, is the difference of the two technologies only about genotyping genomic regions?

[Medhat]

If you need to measure mRNA abundance or expression in cell (which I will assume that this is what you mean by RNA microarray), first mRNA transformed to more stable cDNA. Other than that I do not know what do you mean by RNA microarray.

This is a nice review, that may help to make the idea clear.
DNA microarrays: Types, Applications and their future

[cpad0112]

Do you mean Expression arrays Vs Genotyping arrays (for CNV detection, LOH, genotyping, SNV etc)?

For Expression arrays, RNA (mostly mRNA) is the starting material and probes are designed to detect RNA (qualitative and quantitative).

For SNP/genotyping arrays, starting material is DNA and probes are designed to detect genome level events.

Answer 1

[Aerval]

There isn't such thing as a RNA microarray, its always a DNA microarray (meaning a grid of DNA spots) that is able to measure RNA abundance. It is just that there are also DNA arrays for other sample types like methylation or genotyping

[ebrudermanver]

"We use the term RNA microarrays to refer to arrays used to measure RNA levels, whereas DNA microarrays measure DNA sequence or levels." --- This statement from a book pops up when you search for -"dna microarray" vs "rna microarray"- on Google. I think it is always a DNA microarray, but the naming can be different based on what you measure.

Answer 2

[BioinfGuru]

You should find what you need from these links:

1) Microarray v RNA-seq

2) Advantages of RNA-seq over microarray

3) Paper comparing RNA-Seq and Microarray Transcriptome Profiling

[ebrudermanver]

This response is not replying to my question, unfortunately. What I asked is the difference between DNA microarray and RNA microarray. Both of those are array sequencing methods, while RNA-Seq is something totally different.

[BioinfGuru]

I've never heard of RNA microarray.... you may want to check that.