Exon-intron structures of PHGPx genes putatively encoding glutathione-dependent proteins. (A) The chromosomal structures of PHGPx genes were constructed by comparing mRNA sequences with their respective chromosomal sequences. ORF regions are presented with solid squares in proportion to their relative sizes and the untranslated regions are shown by open squares with a voluntary length. Intervening introns are indicated by solid lines, with a fixed length. The lengths (bp) of each exon and intron are presented at the corresponding positions. The phase of each intron is shown in parenthesis. Orthologous introns having positions and phases shared among PHGPx genes are indicated by vertical solid lines, while those with a certain degree of ambiguity due to highly divergent aa sequences are marked with dotted lines. The exons of platyhelminth genes, which have been further split into the vertebrate orthologs are indicated by gray-toned squares. (B) The structural conservation patterns of GPx7-and GPx8-like genes are similarly analyzed.