Affymetrix Control Program Advances Association Studies and Saves Researchers Time and Money; World's Largest Population Genetics Control Resource Will Provide Free Public Access to Genotype Data on More Than 12,000 Samples.

SANTA CLARA, Calif. -- Affymetrix Inc. (NASDAQ:AFFX) announced today that it is collaborating with leading researchers around the world as part of the Affymetrix Control Program. The program will provide free, public access to control cohort data for whole-genome association studies using Affymetrix GeneChip(R) genotyping arrays. Participating organizations include GlaxoSmithKline, the National Genome Research Network (NGFN) in Germany, Erasmus MC in the Netherlands, the Karolinska Institute in Sweden, the Centre National de Genotypage in France and the Wellcome Trust Case Control Consortium (WTCCC) in the UK.

Genotype data from more than 12,000 samples is in the process of being committed to this unique project, which will make this the world's largest population genetics resource. Use of appropriate control data can reduce the number of control samples required. Researchers can also add age- and sex-matched controls from similar ethnic backgrounds as their cases to increase the genetic power of their current studies.

The data on 9,000 samples will be released through the National Center for Biotechnology Information (NCBI) over the next few months to qualified scientific investigators. In addition, control data from 1,500 samples from the 1958 British Birth Cohort and 1,500 consented blood donors of the UK Blood Services will be released by the WTCCC to qualified scientific investigators. The WTCCC data will be linked to and from the NCBI database. For more information on the WTCCC control data, please visit www.wtccc.org.uk.

"The NCBI's mission is to serve as a public repository for data to help advance scientific research," said Steve Sherry, Ph.D., staff scientist at NCBI. "We are pleased to partner in this program, to not only to distribute the data, but more importantly, to help ensure that they are as useful as possible in benefiting the public health."

"The database will enable researchers from both academia and the pharmaceutical industry to gain a better understanding of population stratification, and how to correct for it when performing large-scale association studies or pharmacogenomics studies," said Professor Stefan Schreiber M.D., one of the two speakers of the NGFN in Germany and researcher from the Christian-Albrechts-University in Kiel, Germany. "The NGFN will provide almost 3,000 control datasets with the two population collections, popgen and KORA-gen.

A multinational team of researchers, organized by Professor Michael Krawczak, Ph.D., and his University colleague Professor Schreiber, are collaborating to create a genetic map of Europe as part of the Affymetrix Control Program. The group is analyzing data to discover markers that could be used to identify different genetic sub-populations on the continent.

To watch a two-part Affymetrix UserForum interview with Professors Schreiber and Krawczak, please visit: http://www.affymetrix.com/userGroup/news/collaborations/schreiber.html

"We have almost finished typing 1,800 samples from the KORA-gen population (www.gsf.de/kora-gen) that will go into the Affymetrix Control Database," said Professor Thomas Meitinger, M.D., director of the Institute of Human Genetics at the GSF - Forschungszentrum fur Umwelt und Gesundheit and member of the NGFN in Germany. "We have started genotyping cases from several diseases for investigators who will use the KORA-gen data as controls."

"We plan to also make our control sample from KORA-gen available in association with P3G (www.p3gconsortium.org), the public population project in genomics," said Professor Erich Wichmann, M.D., Ph.D., GSF Institute of Epidemiology and head of the KORA study.

Affymetrix continues to look for more eligible samples and anticipates that an additional 5,000 to 10,000 samples will be added to this control program over the next year. A sample will be eligible for the controls program if it represents the general population or a control population, and was not selected for having a particular disease phenotype.

"We plan on expanding the Affymetrix control program to include data from populations around the world to better support the broad spectrum of sample types used for genetic studies," said Tom Willis, Ph.D., vice president, DNA Marketing at Affymetrix. "This program, which consists of half a million SNPs across thousands of individuals, will complement the database constructed by the International HapMap Project that included four million SNPs across 210 individuals. It will serve to increase the genetic discovery power for all customers using our whole-genome association products."

To watch the two-part UserForum interview featuring Greg Marcus, Ph.D., senior product manager, DNA Analysis at Affymetrix, please visit: http://www.affymetrix.com/userGroup/analysis/software/marcus.html

About Affymetrix

Affymetrix scientists invented the world's first high-density microarray in 1989 and began selling the first commercial microarray in 1994. Since then, Affymetrix GeneChip(R) technology has become the industry standard in molecular biology research. 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 1,400 systems have been installed around the world and nearly 4,000 peer-reviewed papers have been published using the technology. Affymetrix' patented photolithographic manufacturing process provides the most information capacity available today on an array, enabling researchers to use a whole-genome approach to analyzing the relationship between genetics and health. Affymetrix is headquartered in Santa Clara, Calif., with manufacturing facilities in Sacramento, Calif., and Bedford, Mass. The company maintains important sales and marketing operations in Europe and Asia and has about 1,100 employees worldwide. For more information about Affymetrix, please visit the company's website at www.affymetrix.com.

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: uncertainties relating to the commercial and technological success of the 500K Array Set Control Program discussed in this press release; risks of the Company's ability to achieve and sustain higher levels of revenue, higher gross margins, reduced operating expenses; uncertainties relating to technological approaches, manufacturing, product development; personnel retention; uncertainties related to cost and pricing of Affymetrix products; dependence on collaborative partners; uncertainties relating to sole source suppliers; 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, 2005, 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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