Corporate collegiality hasn't prevented Affymetrix Inc. from suing Synteni Inc., a gene expression microarray (GEM) company, and Incyte Pharmaceuticals Inc., which is acquiring Synteni.

AFFX and INCY have a joint venture under a 1996 agreement to commercialize five AFFX arrays in the expression monitoring field. But under the suit filed last week, AFFX is alleging infringement of its U.S. Patent No. 5,445,934. The patent covers arrays of greater than 1000 oligonucleotides on a solid substrate area of 1 cm
2, including AFFX's GeneChip arrays used for mutation detection and