San Diego-based Illumina, a provider of scientific instruments for genetic analysis, and Hayward-based Solexa, a developer of genetic anaylsis systems, said today that the firms have agreed to a merger where Illumina will acquire Solexa. The stock-for-stock merger is worth approximately $650M. Solexa develops genetic analysis sytems used for microRNA analysis. Illumina said the acquisition would expand its genetic analysis product offerings.