1. Laboratory of Chromosome Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
2. Department of Agronomy, Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, Indiana 47907 and
3. Rosenstiel Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02454
4. Weill Medical College, Cornell University Graduate School of Medical Sciences, New York, New York 10021