Illumina Announces Publication of the Industry's First Peer-Reviewed ChIP-Seq Studies Using Solexa(R) Technology.

Studies Published in Science and Cell Demonstrate a Transformation in Genetic Analysis

SAN DIEGO -- Illumina, Inc., (NASDAQ:ILMN) today announced that researchers from the California Institute of Technology and Stanford University School of Medicine, and the National Heart, Lung, and Blood Institute of the National Institutes of Health are the first in the industry to use the Solexa Sequencing technology with the Genome Analyzer to generate significant chromatin immunoprecipitation sequencing, or ChIP-Seq results within months of system installation, and have study findings accepted for publication by high-profile peer-reviewed journals. These studies appear in the June 8, 2007 edition of Science and the May 18, 2007 issue of Cell, respectively.

In both studies, investigators used Illumina's Solexa Sequencing technology to quickly and easily identify how proteins interact with deoxyribonucleic acid (DNA) across the entire human genome. Findings demonstrate that this next-generation technology offers the scientific community the ability to scan millions of binding sites within one channel of a flow cell for 10 to 30 times lower cost than ChIP-chip approaches. Using the ChIP-Seq method, researchers also obtain unprecedented resolution, specificity, and signal-to-noise as compared to microarray-based alternatives.

"Our ChIP-Seq study took advantage of the Genome Analyzer's ability to generate tens of millions of sequence reads per run," said Richard M. Myers, Ph.D., Professor and Chair of Genetics at Stanford University School of Medicine and key author on the Science publication. "This allowed us to turn ChIP into a simple counting assay, in which one sequence read per molecule of DNA was mapped from the sample back onto the reference genome across millions of molecules per sample. By analyzing the distribution of these positive "hits" across the entire genome we mapped and learned new things about thousands of sites that selectively bind to our factor of interest. The amount and nature of these data meant we got exceptional positional resolution and statistical confidence."

"We are excited about applying other similar "sequence census" methods to measure and map RNA expression, DNA modification assays, and the like," said Barbara Wold, Ph.D., Professor of Molecular Biology and Director of the Beckman Institute at Caltech and key author on the Science paper. "It seems inevitable that sequence reads will soon be the common digital currency for genome-scale DNA and RNA measurements."

According to the paper published in Cell on May 18, 2007, researchers at the NHLBI "demonstrated that direct sequencing of ChIP DNA using the Illumina Genome Analyzer is an efficient method for mapping genome-wide distributions of histone modifications and chromatin protein targets." Investigators used the Solexa sequencing technology to generate genome-wide data for more than 20 epigenetic marks in human T cells.

"As indicated by the Science and Cell studies, scientists are now able to explore entire genomes, regardless of organism type, and unearth rich, new information -- easily, rapidly, and affordably," said John West, Illumina's Senior Vice President and General Manager, DNA Sequencing. "The ChIP-SEQ approach is transforming the way scientists are looking at the DNA-protein interactions that alter gene function and regulation, critical to the understanding of many complex diseases."

Parties interested in hearing more about study findings published in Science are invited to join an Illumina-sponsored webinar, hosted by principal investigators Richard M. Myers, Ph.D., and David Johnson, Ph.D., both from Stanford University Medical Center, and Ali Mortazavi, Ph.D., from The California Institute of Technology on Thursday, June 21, 2007 at 1:00 pm Eastern Time. To register for the event, please visit www.Illumina.com/webinars.

About Illumina's Solexa Sequencing Technology and the Genome Analyzer

Illumina's Solexa Sequencing technology offers a powerful new approach to some of today's most important applications for genetic analysis and functional genomics. Generating one billion bases of high quality DNA sequence per run at less than one percent of the cost of capillary-based methods, the Illumina Genome Analyzer utilizing the Solexa Sequencing technology is designed to enable researchers to dramatically improve the efficiency and speed of current applications.

ChIP-Seq is a sequencing-based alternative to ChIP-chip assays. For ChIP-chip studies, DNA fragments that interact with a protein of interest are identified by hybridization of DNA to the array. When conducting ChIP-Seq, the Solexa Sequencing technology sequences at the end of each segment, allowing researchers to find novel binding cites across the whole genome. For more information, please visit www.illumina.com.

About Illumina

Illumina is a leading developer, manufacturer and marketer of next-generation life science tools and integrated systems for the analysis of genetic variation and biological function. Using our proprietary technologies, we provide a comprehensive line of products and services that currently serve the sequencing, genotyping, and gene expression markets, and we expect to enter the market for molecular diagnostics. Our customers include leading genomic research centers, pharmaceutical companies, academic institutions, clinical research organizations and biotechnology companies. Our tools provide researchers around the world with the performance, throughput, cost effectiveness and flexibility necessary to perform the billions of genetic tests needed to extract valuable medical information from advances in genomics and proteomics. We believe this information will enable researchers to correlate genetic variation and biological function, which will enhance drug discovery and clinical research, allow diseases to be detected earlier and permit better choices of drugs for individual patients.

"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995:

This release may contain forward-looking statements that involve risks and uncertainties. Among the important factors that could cause actual results to differ materially from those in any forward-looking statements are the costs and outcome of Illumina's litigation with Affymetrix and our ability (i) to integrate effectively our recent acquisition of Solexa, Inc., (ii) to develop and commercialize further our BeadArray[TM], VeraCode[TM] and Solexa[R] technologies and to deploy new gene expression and genotyping products and applications for our technology platforms, (iii) to manufacture robust microarrays and Oligator[R] oligonucleotides, (iv) to integrate and scale our VeraCode technology, (v) to scale further oligo synthesis output and technology to satisfy market demand derived from our collaboration with Invitrogen, together with other factors detailed in our filings with the Securities and Exchange Commission including our recent filings on Forms 10-K and 10-Q or in information disclosed in public conference calls, the date and time of which are released beforehand. We disclaim any intent or obligation to update these forward-looking statements beyond the date of this report.