Gene Function and Evolution, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, Barcelona, Spain.|Gene Function and Evolution, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, Barcelona, Spain.|Gene Function and Evolution, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, Barcelona, Spain.|Gene Function and Evolution, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, Barcelona, Spain.