Short communication Phylogenetic analysis with newly characterized Babesia bo6is hsp70 and hsp90 provides strong support for paraphyly within the piroplasms

Heat shock induced stress results in transcrip-tional activation of a conserved set of genes andsynthesis of heat shock-related proteins (hsps),which are present in all eukaryotes and prokary-otes [1]. Heat shock represents an unusual stresssituation for most organisms but, in shuttlingbetween vector and host, parasites are constantlysubjected to such stress [2]. Hsps assist the para-site in adapting to a new host environment duringdifferentiation and invasion [2] and are known tohave a chaperone function, forming complexeswith a diverse array of cellular proteins and pep-tides [3].Hsps offer legitimate targets for the evaluationof phylogenetic relationships since they are highlyconserved, with homology across their entirelength [4]. A target represented by a slowly evolv-ing gene (functionally more constrained) is con-sidered appropriate for studying ancientrelationships rather than more recent subspeciesand strain differences [5]. Each set of hsp se-quences provides unambiguous alignment, ensur-ing positional homology at each character in thedata matrix. Phylogenetic analysis utilizing aminoacid sequence of hsps also provides a large num-ber of parsimony informative characters. Twoadvantages this study has over most apicom-plexan phylogenetic analyses, which use thesmaller PCR products generated from the smallsubunit ribosomal RNA genes, are the larger data