Fig. 3

The NJ tree inferred from the goat, sheep, pig and dromedary TRBV5, TRBV6 and TRBV21 gene sequences. The evolutionary analysis was conducted in MEGA7 [35]. The optimal tree with the sum of branch length = 5.91955883 is shown. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (100 replicates) is shown next to the branches [36]. The tree is drawn to scale with branch lengths in the same units as those of the evolutionary distances used to infer phylogenetic trees. The evolutionary distances were computed using the p-distance method [37] and are in the units of the number of base differences per site. The analysis involved 146 nucleotide sequences. Codon positions included were 1st + 2nd + 3rd + Noncoding. All positions containing gaps and missing data were eliminated. There were a total of 80 positions in the final dataset. The orthologous artiodactyl TRBV subgroups form three major monophyletic grouping: A (TRBV21 genes), B (TRBV5 genes) and C (TRBV6 genes). The different colours highlight the genes within each species, yellow for goat, green for sheep, blue for pig and red for dromedary genes. The gene functionality according to IMGT rules (F: functional, ORF: open reading frame, P: pseudogene) is indicated. The IMGT 6-letter for species (Caphir, Oviari, Susscr and Camdro,) standardized abbreviation for taxon is used