Comparative Genomics Group, Bioinformatics and Genomics Programme, Centre for Genomic Regulation, 88 08003 Barcelona, Spain.|Comparative Genomics Group, Bioinformatics and Genomics Programme, Centre for Genomic Regulation, 88 08003 Barcelona, Spain.|Comparative Genomics Group, Bioinformatics and Genomics Programme, Centre for Genomic Regulation, 88 08003 Barcelona, Spain.