Amino acid alignment of the Amelotin sequences used in our study. The sequences are ordered according to species relationships (see Additional file 1 for names and references). Non-mammalian tetrapod sequences are aligned against the human sequence and four AMTN sequences representative of the main mammalian lineages. The coelacanth (Latimeria) sequence is aligned (only gDNA sequence) at the bottom. Two alternative ends of the opossum AMTN (Monodelphis V1 and V2) are proposed depending on whether or not intraexonic splicing occurs in exon 8 (see text). The specific length of each sequence is indicated in brackets at its end. Signal peptide underlined. SxE and SxxE motifs (encoded by exon 2b and exon 7, respectively) and RGD motif (encoded by the end of exon 8) highlighted in grey. Vertical lines: exon limits; (.): residue identical to human AMTN residue; (−): indel; (?): unknown amino acid; *: stop codon.