Evolutionary history of trypanosomes from South American caiman (Caiman yacare) and African crocodiles inferred by phylogenetic analyses using SSU rDNA and gGAPDH genes

Abstract

In this study, using a combined data set of SSU rDNA and gGAPDH gene sequences, we provide phylogenetic evidence that supports clustering of crocodilian trypanosomes from the Brazilian Caiman yacare (Alligatoridae) and Trypanosoma grayi, a species that circulates between African crocodiles (Crocodilydae) and tsetse flies. In a survey of trypanosomes in Caiman yacare from the Brazilian Pantanal, the prevalence of trypanosome infection was 35% as determined by microhaematocrit and haemoculture, and 9 cultures were obtained. The morphology of trypomastigotes from caiman blood and tissue imprints was compared with those described for other crocodilian trypanosomes. Differences in morphology and growth behaviour of caiman trypanosomes were corroborated by molecular polymorphism that revealed 2 genotypes. Eight isolates were ascribed to genotype Cay01 and 1 to genotype Cay02. Phylogenetic inferences based on concatenated SSU rDNA and gGAPDH sequences showed that caiman isolates are closely related to T. grayi, constituting a well-supported monophyletic assemblage (clade T. grayi). Divergence time estimates based on clade composition, and biogeographical and geological events were used to discuss the relationships between the evolutionary histories of crocodilian trypanosomes and their hosts.

Novel trypanosomeTrypanosoma gillettisp. (Euglenozoa: Trypanosomatidae) and the extension of the host range ofTrypanosoma copemanito include the koala (Phascolarctos cinereus)

“…(KG1) and T. pestanai, as these are the only T. copemani clade isolates with available gGAPDH sequences. The overall topology of the concatenated 18S rDNA and gGAPDH ML tree produced in order to determine the evolutionary position of T. gilletti amongst the trypanosomes was similar to equivalent trees previously presented (Hamilton et al 2007;McInnes et al 2009;Viola et al 2009). The placement of T. gilletti in the T. copemani clade was supported by high aLRT branch support and bootstrap values (99-100%) in the 18S rDNA and gGAPDH analysis individually and in the concatenated analysis.…”

Trypanosoma irwini n. sp (Sarcomastigophora: Trypanosomatidae) from the koala (Phascolarctos cinereus)

“…This is primarily why the gGAPDH locus was also analysed as it is increasingly used in Trypanosoma phylogeny and is under different evolutionary constraints to the 18S rRNA gene (Hamilton et al 2004). The topology of the gGAPDH and concatenated 18S rDNA and gGAPDH trees were nearly identical and very similar to equivalent trees presented by Hamilton et al (2007) and Viola et al (2009). The variation between the gGAPDH and concatenated tree was primarily due to lack of sequence data for the gGAPDH locus as the ' T. irwini' clade only comprised T. irwini and T. bennetti due to T. minasense gGAPDH sequence being unavailable.…”

Diversidade, biologia, filogeografia e taxonomia molecular de tripanossomas de anuros da família Leptodactylidae.

“…Sanguessugas já foram descritas como vetores de tripanossomas de anuros, peixes, tartarugas e serpentes aquáticas (Ferreira et al, 2007Hayes et al, 2014;Jakes et al, 2001;Stevens et al, 2001;Viola et al, 2009b). Algumas espécies de flebotomíneos e culicídeos também foram implicadas como hospedeiras de tripanossomas de anuros (Ferreira et al, 2007 (Figura 2).…”