Genome Bioinformatics Laboratory, Center for Genomic Regulation, Universitat Pompeu Fabra, Pg. Maritim de la Barceloneta 37-49, E-08003, Barcelona, Spain. nuria.lopez@crg.es|Genome Bioinformatics Laboratory, Center for Genomic Regulation, Universitat Pompeu Fabra, Pg. Maritim de la Barceloneta 37-49, E-08003, Barcelona, Spain. nuria.lopez@crg.es|Genome Bioinformatics Laboratory, Center for Genomic Regulation, Universitat Pompeu Fabra, Pg. Maritim de la Barceloneta 37-49, E-08003, Barcelona, Spain. nuria.lopez@crg.es