Affymetrix, Inc. (Nasdaq:AFFX) and the National Institute of Allergy and Infectious Diseases (NIAID)-supported Pathogen Functional Genomics Resource Center (PFGRC) at the J. Craig Venter Institute (JCVI) today announced the launch of the Affymetrix FDA-ECSG custom microarray for identifying and discriminating between different strains of E. coli and Shigella. This custom array was developed for the FDA and is now available to researchers worldwide. Affymetrix and JCVI have collaborated to make this array available from the PFGRC at no cost to researchers through the NIAID-sponsored PFGRC microarray application process.

Approximately 165 million people fall ill and more than a million die worldwide each year after consuming foods contaminated with Escherichia coli (E. coli) and Shigella.¹ These pathogens’ ability to rapidly adapt to new environments requires highly parallel analysis methods to accurately assess their genomic diversity and genomic content.

A custom Affymetrix microarray was developed and validated by analysis of sequenced strains. Using this array, FDA researchers interrogated a collection of E. coli and Shigella strains that were associated with temporally and geographically diverse outbreaks, including the 2006 outbreaks of E. coli linked to lettuce and spinach. The spinach-related outbreak led to 199 infections in 26 states and contributed to three deaths.²

This array design allowed researchers to accurately detect each gene target represented on the array and differentiate closely related strains within a pathotype. While most of the isolates of E. coli O157:H7 associated with the spinach outbreak were indistinguishable, several clinical isolates contained apparent chromosomal rearrangements.

“The results of this investigation carried out by FDA Center for Food Safety and Applied Nutrition (CFSAN) researchers using the Affymetrix FDA-ECSG array demonstrate its great potential for use in evolutionary, epidemiological, and forensics studies for strain identification and discrimination,” said Robert Fleischmann of the JCVI and co-director of the PFGRC.

“We are proud of the researchers who created this custom array that enables identification and discrimination between more strains of E. coli and Shigella than traditional techniques,” said Kevin King, president and CEO of Affymetrix. “To date, Affymetrix has enabled the design of more than 750 custom arrays, and this array is significant as it enables scientists to know more about two foodborne pathogens which have a large impact on human health.”

Affymetrix FDA-ECSG custom microarrays are provided for research purposes only and are not for use in diagnostic procedures. For more information on the array, and to obtain it via the NIAID-sponsored PGFRC microarray application process, visit:

http://pfgrc.jcvi.org/index.php/microarray/affy_array_description/ecoli_shigella/version1.html

¹ Click on the following link and then on the next link for a PDF of the poster containing the FDA research:

http://pfgrc.jcvi.org/index.php/microarray/affy_array_description/ecoli_shigella/version1.html

²http://www.cdc.gov/foodborne/ecolispinach/100606.htm

About Affymetrix

Affymetrix technology is used by the world’s top pharmaceutical, diagnostic and biotechnology companies, as well as leading academic, government and not-for-profit research institutes. More than 1,800 systems have been shipped around the world and more than 18,000 peer-reviewed papers have been published using the technology.

Affymetrix is headquartered in Santa Clara, Calif., and has manufacturing facilities in Cleveland, Ohio, and Singapore. The company has about 1,100 employees worldwide and maintains sales and distribution operations across Europe and Asia. For more information about Affymetrix, please visit the company’s website at www.affymetrix.com.

Forward-looking Statements

All statements in this press release that are not historical are “forward-looking statements” within the meaning of Section 21E of the Securities Exchange Act as amended, including statements regarding Affymetrix’ “expectations,” “beliefs,” “hopes,” “intentions,” “strategies” or the like. Such statements are subject to risks and uncertainties that could cause actual results to differ materially for Affymetrix from those projected, including, but not limited to: risks and uncertainties relating to commercial success of the agreement with the J. Craig Venter Institute discussed in this press release; risks of the company’s ability to achieve and sustain higher levels of revenue, higher gross margins and reduced operating expenses; uncertainties related to technological approaches, manufacturing and product development; personnel retention; uncertainties related to cost and pricing of Affymetrix products; dependence on collaborative partners; uncertainties related to sole-source suppliers; risks associated with past and future acquisitions; uncertainties relating to FDA and other regulatory approvals; competition; risks relating to intellectual property of others and the uncertainties of patent protection and litigation. These and other risk factors are discussed in Affymetrix’ Form 10-K for the year ended December 31, 2008, and other SEC reports, including its Quarterly Reports on Form 10-Q for subsequent quarterly periods. Affymetrix expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Affymetrix’ expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

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