MADISON, WI–June 1 , 2005—NimbleGen® Systems unveiled today a novel technology for rapid microbial resequencing. The ability to identify the genetic variation between a reference genome and closely related microbial isolates is important for studying antibiotic resistance, the evolution of a microbe as it spreads in the public sector, industrial food fermentation, and homeland security, among others. NimbleGen plans to feature this new microbial comparative genomics method at the upcoming American Society for Microbiology (ASM) National Meeting, June 6 - 9, 2005.

NimbleGen's method surveys an entire microbial genome to pinpoint genetic changes, down to the single nucleotide level. The technology relies on a two-stage approach to efficiently identify genomic changes. In stage one, nearly all locations where the strain's genome deviates by even a single nucleotide are detected. In stage two, each nucleotide deviation is resequenced using microarrays to determine the new genetic code, and larger regions of insertion and deletion are also automatically flagged for further characterization using other methods. When compared to alternative microbial mutation discovery and sequencing technologies, NimbleGen's method is significantly faster and less expensive, without any compromise in genotyping accuracy. The overall false positive rate is typically less than one false call per one million bases analyzed.

Baylor College of Medicine used NimbleGen arrays for resequencing genomes of microorganisms that cause syphilis and yaws. "NimbleGen's whole genome resequencing arrays were faster and more cost effective than dideoxy terminator sequencing, with the same high accuracy," said Dr. George Weinstock, Director of the Baylor Human Genome Sequencing Center. "NimbleGen's technology should have a huge impact on the comparative genomics of closely related microbes."

NimbleGen combines its high-capacity 385,000 probe microarrays and novel isothermal probe selection strategy to enable consistent detection of sequence differences between genomes. The flexibility of NimbleGen's Maskless Array Synthesis (MAS) platform provides an additional key benefit: because NimbleGen arrays can be so rapidly and cost-effectively produced, customized arrays-a key component in the second phase of the technique-can finely tile across the regions of genomic difference.

"Other array platforms would require either long lead times to fabricate the arrays, or almost ten-fold more arrays to meet the capacity requirements," stated Dr. Stan Rose, President and CEO of NimbleGen Systems. In the product's early access phase, a customer provided test microbial genome sample where a single SNP had previously been characterized. "In a blind test, we were able to survey the entire genome and find the SNP in three days," he continued. In another study, the microbial comparative genomics technology identified and genotyped more than 500 SNPs in a 4.79Mbp genome, for an overall success rate of >95%.

NimbleGen's microbial comparative genomics method and arrays were used by the Genome Institute of Singapore (GIS) in the product's early access phase to determine the evolution of the SARS virus and its strains. In 2004, GIS published a paper in Genome Research (Wong et al., (2004) 14: 398-405) in which SARS mutation patterns within humans were traced to deduce the infectious source.

For more information, see www.nimblegen.com/cgr/.

About NimbleGen Systems Inc.
NimbleGen Systems is the leading supplier of custom-designed high-density microarray products and services, offering unprecedented flexibility for genomics research. NimbleGen's Maskless Array Synthesis (MAS) technology combines photo-deposition chemistry with digital light projection to shorten array fabrication from months to hours. Customers benefit from extreme flexibility, optimized array design, highly reproducible array fabrication and statistically robust results-all with low cost and quick turnaround. NimbleGen is working with scientists around the world to develop and deploy a wide range of new microarray applications.