¿ Diversa Corp., of San Diego, and The Dow Chemical Co., of Midland, Mich., signed a three-year research and licensing agreement. Diversa will apply its discovery and optimization technologies for Dow to develop a variety of enzymes for multiple chemical processes on a reaction-exclusive basis. The new research agreement is worth $18 million, including technology development fees, research support and milestone payments. Financial terms of the license agreement were not disclosed.

¿ Human Genome Sciences Inc., of Rockville, Md., said that the initial purchaser of its recently completed $100 million private placement exercised its option to buy another $25 million of convertible subordinated notes. The notes are convertible into common stock at a price equal to $52.20 per share. The identity of the purchaser has not been revealed. The stock (NASADQ:HGSI) closed up $1.50 Friday at $51.875. (See BioWorld Today, June 23, 1999, p. 1.)

¿ The Jackson Laboratory, of Bar Harbor, Maine, established a collaboration with the University of California at Davis. The collaboration, which will be called JAX Research Systems at UC Davis, will produce and maintain genetically customized laboratory mice. The mice will be made available to researchers at UC Davis and throughout the West. This program will complement the UC Davis Mouse Biology program.