Affymetrix Announces Launch of Zebrafish and Xenopus laevis Arrays for Whole-Genome Expression Analysis

-- New array delivers the most up-to-date view of the Zebrafish and Xenopus laevis genomes available --

Santa Clara, Calif., Jan. 21, 2004 – Affymetrix, Inc., (NASDAQ: AFFX) today announced the availability of its new GeneChip^® Zebrafish Genome Array and Xenopus laevis Genome Array, which were designed in collaboration with representative members of the Zebrafish and Xenopus laevis research communities and the National Institutes of Health.

The new arrays deliver the most up-to-date view of the Zebrafish and Xenopus laevis genomes. Both organisms are used extensively for developmental studies. The Xenopus laevis Genome Array is the most comprehensive Xenopus laevis expression array commercially available, featuring over 14,400 transcripts. The sequences on the array are drawn from the 2003 drafts of public data sources including GenBank, dbEST and UniGene.  

The Zebrafish Genome Array can be used to study expression of over 14,900 Zebrafish transcripts and is based on the recent 2003 updates to the publicly available RefSeq, GenBank, dbEST and UniGene databases.

“We have collected preliminary data from the Zebrafish array and we are pleased with the array performance,” said Dr. Leonard Zon of Children’s Hospital/Howard Hughes Medical Institute in Boston , Massachusetts . “The Zebrafish array will be an essential tool for our upcoming research.”

“It is exciting that GeneChip arrays are now available for these two important developmental biology model organisms,” said Lianne McLean, Director, Gene Expression Marketing, Affymetrix.  “We worked closely with the Xenopus laevis and Zebrafish research communities to ensure that all of the sequence information used to create these arrays was available in the public databases and that it met their needs.”

One of the benefits of Affymetrix technology is that it enables research groups, such as the barley and Arabidopsis communities, to standardize their expression results on a single platform. This helps ensure consistent and reproducible array results and facilitates data sharing around the world.  

Xenopus laevis and Zebrafish annotation data will be hosted on the NetAffx ä Analysis Center at www.affymetrix.com.

About Affymetrix:

Affymetrix is a pioneer in creating breakthrough tools that are driving the genomic revolution. By applying the principles of semiconductor technology to the life sciences, Affymetrix develops and commercializes systems that enable scientists to improve the quality of life. The Company's customers include pharmaceutical, biotechnology, agrichemical, diagnostics and consumer products companies as well as academic, government and other non-profit research institutes. Affymetrix offers an expanding portfolio of integrated products and services, including its integrated GeneChip platform, to address growing markets focused on understanding the relationship between genes and human health. Additional information on Affymetrix can be found 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 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, market acceptance (including uncertainties relating to product development and market acceptance of the GeneChip^® brand Zebrafish Genome Array and the Xenopus laevis Genome Array) 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, 2002 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.  

NOTE: Affymetrix, the Affymetrix logo, and GeneChip and are registered trademarks owned or used by Affymetrix, Inc.

For further information, please contact:

Sue Charles, CEO Northbank Communications, +44 (0)20 7886 8152, s.charles@northbankcommunications.com

Wes Conard, Senior Manager of Public Relations, +1 (0)408 731 5791