San Diego, California
June 26,  2001

Diversa Corporation (Nasdaq: DVSA) today presented a next-generation evolution technology that improves the efficiency and effectiveness of gene optimization methods. Jay M. Short, Ph.D., President and Chief Executive Officer, explained the benefits of Diversa's tunable GeneReassembly(TM) technology during the BIO 2001 conference in San Diego.

• Unlike traditional, homology-based molecular evolution technologies, GeneReassembly is not restricted by the relatedness of the starting genes used to create new genetic variants.
• The GeneReassembly approach is more effective than traditional gene shuffling techniques for generating diversity.
• GeneReassembly accelerates the rate at which genes and gene pathways can be modified to generate products with desired properties.
• GeneReassembly represents a novel method for structure-based protein generation.

The GeneReassembly platform is an important addition to Diversa's existing suite of complementary evolution technologies, including Diversa's patented Gene Site Saturation Mutagenesis(TM) (GSSM(TM)) (U.S. Patent No. 6,171,820) and PCR-based synthesis shuffling (U.S. Patent No. 5,965,408), which can be applied to optimize both proteins and production of small molecules. Improved product candidates can be identified quickly and efficiently using Diversa's patented and proprietary ultra high-throughput screening technologies, including Diversa's recently announced GigaMatrix(TM) 100,000-well plate screening system. Diversa is using these patented and proprietary technologies to discover and improve products such as environmentally friendly pesticides and herbicides, more efficient enzymes for synthesizing pharmaceutical intermediates, novel antibiotics, and more effective protein therapeutics.

In evolving specific genes or gene pathways of interest, Diversa's GeneReassembly methodology significantly expands the genetic diversity available to be screened, first by creating populations of DNA fragments of varying lengths and then reassembling them via computer-designed DNA ligation to generate new genetic variants. An important advantage of Diversa's GeneReassembly technology is that, unlike the Polymerase Chain Reaction (PCR) and other recombination-based methods, it does not require the use of starting genes having DNA sequence identity, or genetic similarity.

Diversa's tunable GeneReassembly technology explores new genetic diversity by generating multiple gene-sets that differ in crossover frequencies. This computer-controlled system provides for higher degrees of product improvement than may be achievable using traditional, homology-based molecular evolution methods, permits simultaneous optimization of codons, and is enabling for evolving many gene families, including those in which the genes have little or no DNA sequence identity. Diversa's GeneReassembly technology represents the first comprehensive structure-based evolution methodology.

About Diversa

Diversa Corporation is a global leader in developing and applying proprietary technologies to discover and evolve novel genes and gene pathways from diverse environmental sources. Diversa is utilizing its fully integrated approach to develop novel enzymes and other biologically active compounds, such as orally active drugs, produced by these genes and gene pathways. Diversa's
proprietary evolution technologies facilitate the optimization of genes found in nature to enable product solutions for the pharmaceutical, agricultural, chemical processing, and industrial markets. Within these broad markets, Diversa is targeting key multi-billion dollar market segments where it believes its technologies and products will create high value and competitive advantages for strategic partners and customers. Diversa's strategic partners are market leaders and include Aventis Animal Nutrition S.A., Celanese Ltd., Celera Genomics, Finnfeeds International Ltd (a unit of Danisco Cultor), The Dow Chemical Company, GlaxoSmithKline plc, IntraBiotics Pharmaceuticals, Inc., Invitrogen Corporation, and Syngenta Agribusiness Biotechnology Research, Inc. The Company has also formed joint ventures with The Dow Chemical Company (named Innovase LLC) and with Syngenta Seeds AG (named Zymetrics).

Company news release
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