Phylogeny of Triatomine Vectors of Trypanosoma cruzi Suggested by Mitochondrial DNA Sequences

Abstract

The subfamily Triatominae (Hemiptera: Reduviidae) comprises hematophagous insects, most of which are actual or potential vectors of Trypanosoma cruzi, the protozoan agent of Chagas' disease (American trypanosomiasis). DNA sequence comparisons of mitochondrial DNA (mtDNA) genes were used to infer phylogenetic relationships among 32 species of the subfamily Triatominae, 26 belonging to the genus Triatoma and six species of different genera. We analyzed mtDNA fragments of the 12S and 16S ribosomal RNA genes (totaling 848-851 bp) from each of the 32 species, as well as of the cytochrome oxidase I (COI, 1447 bp) gene from nine. The phylogenetic analyses unambiguously supported several clusters within the genus Triatoma. In the morphological classification, T. costalimai was placed tentatively within the infestans complex while T. guazu was not included in any Triatoma complex. The placement of these species in the molecular phylogeny indicated that both belong to the infestans complex. We confirmed with a strong support the inclusion of T. circummaculata, a member of a different complex based on morphology, within the infestans complex. On the other hand, the present phylogenetics analysis did not support the monophyly of the infestans complex species as it was suggested in our previous studies. While no strong inference of polyphyly of the genus Triatoma was provided by the bootstrap analyses, the other species belonging to Triatomini analyzed could not be distinguished from the species of Triatoma.

Biological and genetic aspects of crosses between species of the genus Meccus (Hemiptera: Reduviidae Triatominae)

“…In accordance with these species and subspecies concepts and in light of some previously published reports (Flores et al 2001, Martínez et al 2005, Takashi-Obara et al 2007, Bargues et al 2008, the biological evidence reported here supports the proposition that it is more appropriate to attribute a subspecies level to M. bassolsae, as has been proposed for M. pallidipen nis, M. longipennis and M. picturatus (Martínez-Ibarra et al 2008b). However, the same biological evidence supports the proposal that M. phyllosomus is a full spe cies, as some recent molecular studies have proposed (Sainz et al 2004, Pfeiler et al 2006.…”

“…Biological and molecular studies on typical specimens (Mazzotti & Osorio 1942, Bargues et al 2008, Martínez-Ibarra et al 2008b) and on the naturally crossbred descendents of different individuals from sympatric populations (M. pallidipennis, M. longipennis and M. picturatus) (Martínez-Ibarra et al 2009) have lead to a proposal to reclassify some (M. pallidipennis, M. longipennis and M. picturatus) (Marcilla et al 2001, Martínez-Ibarra et al 2008b or all (Bargues et al 2008 of the six species of the genus Meccus to subspecies of M. phyllosomus. Other molecular and biological studies support the consideration of these groups as full species (Sainz et al 2004, Pfeiler et al 2006, Martínez-Ibarra et al 2008b). However, molecular evidence (Bargues et al 2008) supports the revalidation of the genus Meccus for the six species traditionally grouped into the Phyllosoma complex (Carcavallo et al 2000).…”

Biological and genetic aspects of experimental hybrids from species of the Phyllosoma complex (Hemiptera: Reduviidae: Triatominae)

“…These studies, showing biological evidence for the low degree of reproductive isolation among these four species of the genus Meccus, have been enhanced by recent molecular studies (Bargues et al 2000, Marcilla et al 2001) that support the proposition that six species of the Phyllosoma complex (including M. phyllosomus and M. bassolsae) should be considered as subspecies. On the other hand, other molecular studies (Sainz et al 2004, Pfeiler et al 2006) consider these species as valid ones. Since this debate has continued, knowledge about the degree of reproductive isolation of species of the Phyllosoma complex still needs to be improved.…”

Molecular research and the control of Chagas disease vectors

“…Several DNAbased techniques have been hitherto applied to triatomines Lyman 1999, Monteiro et al 2001). These include randomly amplified polymorphic DNA (RAPD) (Carlier et al 1996, Dujardin et al 1998a, Noireau et al 2000a, Borges et al 2000, Jaramillo et al 2001, Pacheco et al 2003, species-specific length variation of rDNA amplicons (Jaramillo et al 2001), single strand conformational polymorphism analysis , sequencing of selected nuclear (Monteiro et al 2000, 2001 and mitochondrial gene fragments (García and Powell 1998, García et al 2001, Gaunt and Miles 2002, Hypša et al 2002, Sainz et al 2004, and characterization of polymorphic microsatellite markers (Harry et al 1998, Anderson et al 2002). …”