PROFILING TECHNIQUE: MICROARRAY ANALYSIS

The human genome contains approximately 20,000 genes. At any given moment, each of our cells has some combination of these genes turned on, and others are turned off. How do scientists figure out which are on and which are off?

Scientists can answer this question for any cell sample or tissue by gene expression profiling, using a technique called microarray (pronounced MY-crow-ah-ray) analysis.

Microarray analysis involves breaking open a cell, isolating its genetic contents, identifying all the genes that are turned on in that particular cell and generating a list of those genes.

	What is a DNA Microarray? A DNA micorarray allows scientists to perform an experiment on thousands of genes at the same time. Each spot on a microarray contains multiple identical strands of DNA. The DNA sequence on each spot is unique. Each spot represents one gene. Thousands of spots are arrayed in orderly rows and columns on a solid surface (usually glass). The precise location and sequence of each spot is recorded in a computer database. Microarrays can be the size of a microscope slide, or even smaller.

Supported by a Science Education Partnership Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the National Institutes of Health, Department of Health and Human Services. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.