Section: New Results

Comparison of peak finding methods applied to tiling array experiments

Participant : Guillemette Marot.

Scan statistics are widely used to detect peaks in tiling array experiments. An extensive analysis study of real biological data is being performed with Florent Sebbane and David Hot teams (Institut Pasteur, Lille) for the study of the Yersinia Pestis bacteria in order to find new small RNAs. First results have been presented in [31] . Given a signal composed of intensities ordered along the genome, the statistical problem is to detect peaks, taking into account the irregular design of the chips, which the biologists had chosen a few years ago. A master student (D. Thuillier) has compared different normalisation methods during a 6 months internship and improved the first analysis results presented in [31] . We also propose a local score procedure, which seems promising according to first biological results obtained. The next step is to work with Alain Célisse in order to choose a generative model on the normalised data which would enable to give appropriate initial values to the local score procedure and associate p-values to local scores.