Graphical comparison of the exons and intron-exon boundaries of human and canine TTC8. (A) Mouse (Mus muscularis) TTC8. (B) Human (Homo sapien) TTC8. (C) Canine (Canis familiaris) TTC8 as predicted by Ensembl genebuild. Thirteen of the genebuild exons predicted are identical to the human exons (black). Exon 2 (grey) is different at the 3′ intron-exon boundary. Exons 3, 8, 9 and 10 (grey) show no sequence or size similarity to their human equivalents and are probably incorrect. (D) Canine TTC8 exons confirmed by sequencing the retinal mRNA transcript. Exon 2A has not been predicted by Ensembl genebuild. The location of the sequence variant is indicated.