Conservation of exon intron structures in related genes from human, fly, and worm. The exon and intron structures of related genes from human, fly, and worm are showed, (A): E2F1-6 family, (C): RB family, and Protein sequences alignments of the region with interspecies conserved exons are also showed, (B): E2F1-6 family, (D): RB family. Boxes correspond to exons. Non-coding exons are shown in grey. The interspecies conserved exons are labeled with red color. The size of introns and exons in nucleotides is shown. Introns and non-coding regions are not drawn to scale. In the alignment, the protein sequences coded by interspecies conserved exons are labeled with blue color, and amino acid residues overlap splice sits are labeled with red color. The exon intron structures information are got from ensemble data base, detail of transcripts used for analysis are: E2F4-Hs: ENST00000379378; E2F5-Hs: ENST00000416274; E2F2-Dm: FBtr0081501; EFL1-Ce: Q9XX87_CAEEL (Y102A5C.18); RBL1-Hs: ENST00000373664; RBL2-Hs: ENST00000262133; RB1-Hs: ENST00000267163; RBF1-Dm: FBtr0070146. The exon intron structures of all E2F1-6 and RB Family genes from human, fly, and worm can be found in additional file 6.