Phylogenetic rooted tree analysis of the CTSD protein by using the neighbor joining method of MEGA (version 5.0). The degree of confidence for each point was determine by bootstrap analysis (500 repetitions). The CTSD sequences of Ovisarise, Capra hircus, Bos taurus, Sus scrofa, Homo sapiens, Mus musculus, Anas platyrhynchos, Gallus were obtained from GenBank (XP_027815055.1, XP_017898833.1, XP_005227353.1, NP_001032810.1, CAG33228.1, NP_034113.1, XP_027313685.1, NP_990508.1).