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(Circulation. 2008;118:1593-1597.)
© 2008 American Heart Association, Inc.

Statistical Primer for Cardiovascular Research

Genetics and Genomics

Gene Expression Microarrays

Karla V. Ballman, PhD

From the Division of Biostatistics, Mayo Clinic, Rochester, Minn.

Correspondence to Karla V. Ballman, PhD, Division of Biostatistics, Mayo Clinic, Harwick 8, 200 First St SW, Rochester, MN 55905. E-mail ballman@mayo.edu

Key Words: gene expression microarrays • genes • statistics

An extract of the first 250 words of the full text is provided, because this article has no abstract.

	Introduction

 
Since its development almost 2 decades ago, gene expression microarray technology has generated excitement and raised expectations for dramatic discoveries of underlying disease mechanisms. The general concept of a gene expression microarray is relatively straightforward. Messenger RNA is extracted from a biospecimen. Examples of biospecimens include cells grown in culture, tissue from animal models, and human tissue. The messenger RNAs are converted into DNA, labeled with a fluorescent dye, and hybridized to a slide containing probes corresponding to target genes of interest arranged in a matrix format. The level of gene expression is estimated from the raw intensities of the fluorescence emitted by the labeled sequence bound to probes representing genes from which messenger RNAs were transcribed. Various different platforms are available to measure gene expression levels. Some are single-channel arrays in which 1 sample is hybridized on each array; others are 2-channel arrays in which 2 samples are hybridized simultaneously on a single array with 2 different fluorescent dyes. Some platforms are all-purpose standard arrays manufactured on a large scale that typically interrogate the expression level of all known genes. There also are custom arrays available that measure the expression levels of genes known to be associated with a particular disease or genes of interest to an individual researcher. Throughout this article, the term microarray is used to refer to a gene expression microarray.

The intent of the present article is to present an overview of the statistical components related to the design and analysis of a microarray experiment. . . . [Full Text of this Article]