Microarray Experiment Overview

How are DNA microarrays used to study gene expression patterns?

The basic approach is to measure the levels of all messenger RNAs (mRNAs) present in a cell. The underlying assumption is that if a gene is being transcribed to mRNA, then the gene is being expressed.

The microarray is made from short pieces of DNA from all the genes in the genome. Deciding on exactly which sequences should represent the gene on the microarray is a complicated process. For simplicity’s sake, we’ll assume that each spot represents a single gene.

An illustration of a tumor with an arrow pointing to a piece of D-N-A with 3 nucleotides highlighted. To the right of the D-N-A is an arrow pointing to a microarray chip. To the right of the microarray chip is an arrow pointing to a microarray.