Hej Erik, The first singular value is: 1.9071 The first principal component has the following values for each variable (PIP): -0.3288 -0.3763 -1.0907 0.9091 -1.5176 -0.7170 -1.6430 -1.1700 -0.2144 1.4566 0.2295 -0.7296 -1.0471 The first principal component has the following values for each sample (these are the ones you want to plot): 0.8878 0.9211 1.1391 0.8372 1.3336 0.8283 0.7192 0.7994 0.9854 1.5206 0.7769 0.9962 1.3031 0.8699 0.6403 --------------------------------------------------------- Example: This means that according this model, for instance, the logarithm of the relative expression value of the 1st gene for the 1st sample should be 1.9071 * -0.3288 * 0.8878 Similarly, the logarithm of the relative expression value of the 2nd gene for the 3rd sample should be 1.9071 * -0.3763 * 1.1391 --Johan