Microsatellite-containing cosmid clones were selected from a cosmid library by screening with poly(dAdC).poly(dGdT)(Pharmacia). Clones containing satellite sequence were eliminated by a secondary screen with the insert fumi a clone containing sequences similar to the bovine 1.709 satellite.' Sequelice flanking the microsatellite repeat was obtained in one direction by priming from the repeat itself using a modification of the Browne & Litt (1991) method' and by cycle stymiring with \'ent polymerase (NewEngland Biolabs).A primer W;IS designed from the sequence obtained to allow sequencing through the microsatellite repeat and into the sequence beyond, which enabled a second primer to be designed to PCR amplify the niit:rosatelli te containing region.