Mitochondrial DNA sequence variation among triatomine vectors of Chagas' disease

Kissing bugs or triatomines (Reduviidae: Triatominae) are vectors of the Ch agas' disease agent Trypanosoma cruzi. There is a current need for more sen sitive tools for use in discrimination of different bug populations and spe cies, thus allowing a better understanding of these insects as it relates t o disease transmission and control. In a preliminary analysis of the mitoch ondrial large subunit ribosomal RNA (mtlsurRNA) and cytochrome B (mtCytB) g enes, we used DNA sequencing to study species identification and phylogeny. In both examined gene regions, about 46% of nucleotide positions exhibited polymorphism. The examined region of mtCytB appears to have evolved more r apidly than the examined region of mtlsurRNA. Phylogenetic analysis of both gene fragments in the examined species produced similar results that were generally consistent with the accepted taxonomy of the subfamily. The two m ajor tribes, Rhodniini and Triatomini, were supported, along with additiona l clades that corresponded to accepted species complexes within the Rhodniu s and Triatoma genera. The one chief exception was that Psammolestes coreod es sorted into the Rhodnius prolixus-robustus-neglectus clade, with bootsra p values of 99% and 81%, respectively, for the mtlsurRNA and mtCytB fragmen ts. All of the individual species examined could be distinguished at both g enetic loci.