Bioinformatics and Genomics Group, Centre for Genomic Regulation (CRG) and Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain. david.gonzalez@crg.eu|Bioinformatics and Genomics Group, Centre for Genomic Regulation (CRG) and Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain. david.gonzalez@crg.eu|Bioinformatics and Genomics Group, Centre for Genomic Regulation (CRG) and Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain. david.gonzalez@crg.eu|Bioinformatics and Genomics Group, Centre for Genomic Regulation (CRG) and Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain. david.gonzalez@crg.eu