Can someone point out for me where to find a package to do principal component analysis for Affy data, if existing? Thanks, Yongde Yongde Bao, Ph.D Biomolecular Research Facility Department of Microbiology University of Virginia School of Medicine Charlottesville, VA 22908 E-mail: yb8d at virginia.edu Voice mail: 434-982-2551, 434-924-2553 FAX: 434-982-2514