DNA Microarray Testing

DNA microarray testing is a major technological advance that allows researchers to analyze the gene expression of thousands of different genes in a single experiment. Although still in its infancy, this technology is an important tool in the study of genetics.

Gene Expression

• Human DNA consists of approximately 3 billion bases, more than 99 percent of which are the same in all people.

  Nearly every cell in the body contains a full set of chromosomes and identical genes. However, only a fraction of these genes confer their unique properties in what is called "gene expression." DNA is the repository of genetic information. Through gene expression, DNA is transcribed into messenger RNA (mRNA) molecules and translated into proteins that carry out cell functions.

Purpose

• Before a cell divides, the DNA replicates and transcribes into RNA, which then builds proteins.

  Through DNA microarray testing, scientists can study gene expression and gain insight into the fundamental aspects of cell growth and function, as well as the genetic causes of diseases, and how different drugs and therapies affect them.

DNA Microarrays

• DNA microarray testing reveals how genes work together and interact.

  A DNA microarray generally comprises hundreds or thousands of gene sequences arranged in a regular pattern on a membrane or glass slide. By hybridizing these samples with fluorescently tagged nucleic acid molecules that bind to complementary genes, scientists can create a colored digital image that reveals patterns of gene expression.

The Human Genome Project

• DNA microarray technology can analyze, compare and label gene sequences.

  The Human Genome Project (HGP), a 13-year multinational government study completed in 2003, identified approximately 25,000 genes and sequenced over 3 billion base pairs in human DNA. Scientists are using DNA microarray testing to investigate and classify the genes identified by the HGP.