SANTA CLARA, Calif., July 26 -- Applied Imaging Corp. has purchased Vysis, Inc.'s cytogenetic imaging instrumentation business. As part of the transaction, Vysis has taken an equity stake of approximately four percent in Applied Imaging. The two companies have agreed that Applied Imaging will focus its sales and product development efforts on cytogenetic imaging instrumentation, while Vysis will concentrate its resources on its proprietary DNA probe business FISH technology and on GenoSensor, its newly developed genomic microarray platform.