41 Chapter 2 A fast and efficient gene expression test to discriminate between osteoblasts and fibroblasts in culture Marga Wilkens, Krista A. Kooi, Edo A.D. Plantinga, Gerard J. te Meerman, Robert M.W. Hofstra, Charles H.C.M. Buys, Frans Gerbens Department of Medical Genetics, University Medical Center Groningen, Groningen, The Netherlands Submitted