San Diego, California
April 2, 2003

TGR technology strengthens Diversa's DirectEvolution patent portfolio

Diversa Corporation (Nasdaq: DVSA) announced that it has been granted U.S. Patent No. 6,537,776 directed to Tunable GeneReassembly(TM) (TGR(TM)), the next-generation evolution technology that improves the efficiency and effectiveness of gene optimization methods. The TGR platform is an important addition to Diversa's existing estate of complementary, patented DirectEvolution® technologies, which can be applied to optimize proteins, such as antibodies and enzymes, as well as gene pathways and whole cells. Diversa's suite of DirectEvolution technologies is protected by numerous issued patents, including: Gene Site Saturation Mutagenesis(TM) (GSSM(TM)) (U.S. Patent Nos. 6,171,820 and 6,579,258), Exonuclease-Mediated Gene Assembly in Directed Evolution (U.S. Patent Nos. 6,361,974 and 6,352,842), End Selection in Directed Evolution (U.S. Patent Nos. 6,358,709 and 6,238,884), Recombination-Based Synthesis Shuffling (U.S. Patent Nos. 5,965,408 and 6,440,668, and Australian Patent No. AU724521), and Directed Evolution of Thermophilic Enzymes (U.S. Patent Nos. 5,830,696 and 6,335,179).

The TGR technology gives Diversa an advantage in developing products, such as more efficient
enzymes for synthesizing pharmaceutical intermediates, new animal feed enzymes, and industrial
processing enzymes. Diversa has utilized its proprietary genomic discovery technologies to produce
gene libraries that are estimated to contain the entire genomes of over three million microorganisms, which can be used to deliver the best genetic starting points for applying evolution technologies. Unlike
recombination-based (or "PCR- based") methods, the TGR technology does not require the starting genes to have significant DNA sequence identity, or genetic similarity. Accordingly, highly diverse genes can be blended using the TGR technology to create additional genetic diversity based solely on amino acid or protein structure. By using segments from diverse genes, the Tunable GeneReassembly technology permits unparalleled freedom in optimizing product candidates for a particular application.
Diversa has patented the combination of its discovery and evolution technologies (U.S. Patent No. 5,939,250) with the goal of delivering improved products for pharmaceutical, agricultural, and chemical / industrial applications.

In addition, the Tunable GeneReassembly technology is a powerful component of Diversa's de novo human antibody program, which is aimed at creating fully- human antibodies in vitro that are designed to incorporate optimal stability, functionality, and diversity, without the limitations of hybridoma technologies or transgenic animals. The combination of Diversa's DirectEvolution technologies and ultra high-throughput screening capabilities has yielded a large in vitro library of fully-human antibodies. This library has been expressed in mammalian cells and validated by successfully identifying a human antibody against a known antigen.

Diversa's Tunable GeneReassembly methodology explores new genetic diversity by utilizing a computer-controlled system to generate multiple gene- sets that differ in crossover frequencies. This method allows higher degrees of product improvement than may be achievable using traditional, homology- based molecular evolution methods and thus, represents a next-generation evolution method in which crossover selection is not governed by DNA polymerases. The TGR technology allows structural information to be incorporated into crossover point decisions, permits simultaneous
optimization of codons, and enables evolution of many gene families, including those in which the starting genes have little or no DNA sequence identity. For example, in the case of a gene family that is mutation sensitive, crossover frequencies can be programmed in one scenario to reflect recombination-based DNA shuffling; however, if the gene family to be blended is more resilient to mutations, crossover frequency can be increased accordingly to surpass the capabilities of standard shuffling approaches. Finally, the Tunable GeneReassembly technology accelerates the rate at which genes and gene pathways can be modified to generate products with desired properties.

Diversa Corporation is a leader in applying proprietary genomic technologies for the rapid discovery and optimization of novel products from genes and gene pathways. Diversa is directing its integrated portfolio of technologies to the discovery, evolution, and production of commercially valuable molecules with pharmaceutical applications, such as optimized monoclonal antibodies and orally active drugs, as well as enzymes and small molecules with agricultural, chemical, and industrial applications. In addition, the Company has formed alliances and joint ventures with market leaders, such as
Celera Genomics, The Dow Chemical Company, DuPont Bio-Based Materials, GlaxoSmithKline plc, Invitrogen Corporation, and affiliates of Syngenta AG. Additional information is available at Diversa's website: www.diversa.com .

Diversa, DirectEvolution®, Tunable GeneReassembly, TGR, Gene Site Saturation Mutagenesis, and GSSM, are U.S. trademarks of Diversa Corporation.