A molecular phylogeny of the benignTheileriaparasites based on major piroplasm surface protein (MPSP) gene sequences

Abstract

SUMMARYTo investigate the phylogeny of benignTheileriaparasites, we determined the complete major piroplasm surface protein (MPSP) gene sequences for 6 benign theilerial organisms, including the first from tick. Sequences were analysed alongside published sequences for 39 benignTheileriaparasites, using Bayesian inference and maximum parsimony. All MPSP sequences were 852 nucleotides, except for Gansu, Wuchangbuf, VB01, and VB01; Gansu contained 873 nucleotides, and the other 3 had 855. Deduced amino acid sequences contained 284 residues, except for Gansu (291) and Wuchangbuf, VB01, and VB01 (285 each). Pairwise comparisons showed identities among 45 theilerial MPSP sequences ranging from 70·9 to 99·8% for nucleotide and 71·0 to 100% for amino acid sequences. Our results clearly indicate that all global parasites, excluding Brisbane, were classified into 1 of 8 types; 6 types ofTheileriaexist in Korea. Each type, excluding Type 6, has several type-specific amino acid sequences. The phylogenetic tree derived from the nucleotide sequences showed 2 sister-group relationships, Type 2+Type 7 and Type 3+Brisbane, with a new branching pattern: (Type 6 (Type 8 ((Type 2, Type 7), (Type 1, (Type 4, (Type 5, (Type 3, Brisbane))))))). Our sequence data showed no geographical influence on worldwideTheileriaparasite distribution.