Phylogenetic tree of mammalian IL-17A protein sequences. Evolutionary sequence comparisons were undertaken using 13 selected mammalian and other IL-17A sequences by initially conducting a multiple alignment using Clustal Omega (EMBL/EBI online, ). The evolutionary relationships between the sequences were inferred using Mr. Bayes launched from TOPALI v 2.5 using the Jones–Taylor–Thornton plus gamma (JTT + G) model with two runs each of 1 250 000 generations with a burn in period of 20% and sampling frequency of 1000. The horizontal lines are branches whose length represents the amount of genetic change over time. The scale bar shows the distance represented by 0.1 expected substitutions per site. The robustness of the clustering of sequences are shown by the Bayesian Posterior Probabilities at the nodes. Accession numbers of the sequences used for the comparison are: Human NP_002181.1; House mouse NP_034682.1; Cow NP_001008412.1; Sheep XP_004018936.1; Goat NP_001272654.1; Horse NP_001137264.1; Pig NP_001005729.1; Dog NP_001159350.1; Domestic guinea pig NP_001265697.1; Koala AHZ08738.1; Chicken NP_989791.1; EGW10039.1 Chinese hamster and European rabbit AMQ91106.1. The phylogenetic tree was annotated using Dendroscope.