Fig. (2) Exon-intron structures of four groups of mob genes. Exon-intron structures of mob genes are analyzed using Spidey program or directly obtained from Ensembl. Phase0 introns are indicated by open rectangles, phase1 by dark rectangles and phase2 by gray ones. Three kinds of arrow symbols (circle, triangle and rectangle) point to three categories of conserved splicing sites among intra- and inter-groups of mob genes. These three categories of conserved introns are assigned as intron1, 2 and 3, respectively. The flanking introns are named according to their relative positions with intron1, 2 and 3, such as minus1, 2 etc as going upstream and plus 1, 2 etc as going downstream. The numberings of introns are indicated on top of their corresponding positions unless they have the same nominations as their immediate upper sequences. The dashes with two slashes in the middle represent the unscaled sequence lengths at the ends; otherwise the lengths of all sequences are scaled based on the numbers of nucleotides in exons.