We detect common confounding factors using probabilistic principal component analysis modeled by gaussian process latent variable models (GPLVM) [Lawrence2004]. This probabilistic approach to detect low dimensional significant features can be interpreted as detecting common confounding factors in time series experiments by applying GPLVM in advance to two-sample tests of [Stegle2010] on the whole dataset. Two-sample tests on Gaussian Processes decide differential expression based on the bayes factor of marginal probabilities for control and treatment being modeled by one common or two separate underlying function(s). As GPLVM is based on Gaussian Processes it provides a covariance structure of confounders in the dataset. We take this covariance structure between features to build up a two-sample Gaussian Process model taking confounding factors throughout the dataset into account.
To account for confounding factors in gptwosample simply at the option -c N to the run call, where N is the number of confounding factors to learn.