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Phylogeographic pattern and extensive mitochondrial DNA divergence disclose a species complex within the Chagas disease vector Triatoma dimidiata.

Monteiro FA, Peretolchina T, Lazoski C, Harris K, Dotson EM, Abad-Franch F, Tamayo E, Pennington PM, Monroy C, Cordon-Rosales C, Salazar-Schettino PM, Gómez-Palacio A, Grijalva MJ, Beard CB, Marcet PL - PLoS ONE (2013)

Bottom Line: We propose that Groups I-IV, as well as T. hegneri, should be regarded as separate species.In the Petén of Guatemala, representatives of Groups I, II, and III occur in sympatry; the absence of haplotypes with intermediate genetic distances, as shown by multimodal mismatch distribution plots, clearly indicates that reproductive barriers actively promote within-group cohesion.Some sylvatic specimens from Belize belong to a different species - likely the basal lineage of the T. dimidiata complex, originated ~8.25 Mya.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Epidemiologia e Sistemática Molecular, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, Brazil. fermonte@globo.com

ABSTRACT

Background: Triatoma dimidiata is among the main vectors of Chagas disease in Latin America. However, and despite important advances, there is no consensus about the taxonomic status of phenotypically divergent T. dimidiata populations, which in most recent papers are regarded as subspecies.

Methodology and findings: A total of 126 cyt b sequences (621 bp long) were produced for specimens from across the species range. Forty-seven selected specimens representing the main cyt b clades observed (after a preliminary phylogenetic analysis) were also sequenced for an ND4 fragment (554 bp long) and concatenated with their respective cyt b sequences to produce a combined data set totalling 1175 bp/individual. Bayesian and Maximum-Likelihood phylogenetic analyses of both data sets (cyt b, and cyt b+ND4) disclosed four strongly divergent (all pairwise Kimura 2-parameter distances >0.08), monophyletic groups: Group I occurs from Southern Mexico through Central America into Colombia, with Ecuadorian specimens resembling Nicaraguan material; Group II includes samples from Western-Southwestern Mexico; Group III comprises specimens from the Yucatán peninsula; and Group IV consists of sylvatic samples from Belize. The closely-related, yet formally recognized species T. hegneri from the island of Cozumel falls within the divergence range of the T. dimidiata populations studied.

Conclusions: We propose that Groups I-IV, as well as T. hegneri, should be regarded as separate species. In the Petén of Guatemala, representatives of Groups I, II, and III occur in sympatry; the absence of haplotypes with intermediate genetic distances, as shown by multimodal mismatch distribution plots, clearly indicates that reproductive barriers actively promote within-group cohesion. Some sylvatic specimens from Belize belong to a different species - likely the basal lineage of the T. dimidiata complex, originated ~8.25 Mya. The evidence presented here strongly supports the proposition that T. dimidiata is a complex of five cryptic species (Groups I-IV plus T. hegneri) that play different roles as vectors of Chagas disease in the region.

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Median-joining haplotype network based on T.dimidiata and T. hegneri cytochrome b haplotypes.The size of the circles on the network is proportional to haplotype frequency. Small red circles represent missing haplotypes. Network circle colors are the same as in Fig. 1. Circles with dotted red outlines denote the presence of haplotypes from Guatemala, Petén among groups I and II.
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pone-0070974-g003: Median-joining haplotype network based on T.dimidiata and T. hegneri cytochrome b haplotypes.The size of the circles on the network is proportional to haplotype frequency. Small red circles represent missing haplotypes. Network circle colors are the same as in Fig. 1. Circles with dotted red outlines denote the presence of haplotypes from Guatemala, Petén among groups I and II.

Mentions: Both cyt b and cyt b+ND4 tree topologies indicate the existence of four well-defined monophyletic groups: Group I includes samples from Mexico (Chiapas), Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Ecuador, and Colombia; Group II comprises the westernmost samples from Mexico but also includes specimens from Tabasco and Petén; Group III includes specimens from Petén (Guatemala), Yucatán (Mexico), and Belize; and Group IV includes sylvatic samples from Belize. T. hegneri, from the island of Cozumel, Mexico, appears as yet another independent lineage within the range of between-group variability observed (Figures 2 and 3). Mean Kimura 2-parameters pairwise cyt b genetic distances among Groups I–IV plus T. hegneri were very high, ranging from 0.080 to 0.155 (Table 3).


Phylogeographic pattern and extensive mitochondrial DNA divergence disclose a species complex within the Chagas disease vector Triatoma dimidiata.

Monteiro FA, Peretolchina T, Lazoski C, Harris K, Dotson EM, Abad-Franch F, Tamayo E, Pennington PM, Monroy C, Cordon-Rosales C, Salazar-Schettino PM, Gómez-Palacio A, Grijalva MJ, Beard CB, Marcet PL - PLoS ONE (2013)

Median-joining haplotype network based on T.dimidiata and T. hegneri cytochrome b haplotypes.The size of the circles on the network is proportional to haplotype frequency. Small red circles represent missing haplotypes. Network circle colors are the same as in Fig. 1. Circles with dotted red outlines denote the presence of haplotypes from Guatemala, Petén among groups I and II.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3733668&req=5

pone-0070974-g003: Median-joining haplotype network based on T.dimidiata and T. hegneri cytochrome b haplotypes.The size of the circles on the network is proportional to haplotype frequency. Small red circles represent missing haplotypes. Network circle colors are the same as in Fig. 1. Circles with dotted red outlines denote the presence of haplotypes from Guatemala, Petén among groups I and II.
Mentions: Both cyt b and cyt b+ND4 tree topologies indicate the existence of four well-defined monophyletic groups: Group I includes samples from Mexico (Chiapas), Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Ecuador, and Colombia; Group II comprises the westernmost samples from Mexico but also includes specimens from Tabasco and Petén; Group III includes specimens from Petén (Guatemala), Yucatán (Mexico), and Belize; and Group IV includes sylvatic samples from Belize. T. hegneri, from the island of Cozumel, Mexico, appears as yet another independent lineage within the range of between-group variability observed (Figures 2 and 3). Mean Kimura 2-parameters pairwise cyt b genetic distances among Groups I–IV plus T. hegneri were very high, ranging from 0.080 to 0.155 (Table 3).

Bottom Line: We propose that Groups I-IV, as well as T. hegneri, should be regarded as separate species.In the Petén of Guatemala, representatives of Groups I, II, and III occur in sympatry; the absence of haplotypes with intermediate genetic distances, as shown by multimodal mismatch distribution plots, clearly indicates that reproductive barriers actively promote within-group cohesion.Some sylvatic specimens from Belize belong to a different species - likely the basal lineage of the T. dimidiata complex, originated ~8.25 Mya.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Epidemiologia e Sistemática Molecular, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, Brazil. fermonte@globo.com

ABSTRACT

Background: Triatoma dimidiata is among the main vectors of Chagas disease in Latin America. However, and despite important advances, there is no consensus about the taxonomic status of phenotypically divergent T. dimidiata populations, which in most recent papers are regarded as subspecies.

Methodology and findings: A total of 126 cyt b sequences (621 bp long) were produced for specimens from across the species range. Forty-seven selected specimens representing the main cyt b clades observed (after a preliminary phylogenetic analysis) were also sequenced for an ND4 fragment (554 bp long) and concatenated with their respective cyt b sequences to produce a combined data set totalling 1175 bp/individual. Bayesian and Maximum-Likelihood phylogenetic analyses of both data sets (cyt b, and cyt b+ND4) disclosed four strongly divergent (all pairwise Kimura 2-parameter distances >0.08), monophyletic groups: Group I occurs from Southern Mexico through Central America into Colombia, with Ecuadorian specimens resembling Nicaraguan material; Group II includes samples from Western-Southwestern Mexico; Group III comprises specimens from the Yucatán peninsula; and Group IV consists of sylvatic samples from Belize. The closely-related, yet formally recognized species T. hegneri from the island of Cozumel falls within the divergence range of the T. dimidiata populations studied.

Conclusions: We propose that Groups I-IV, as well as T. hegneri, should be regarded as separate species. In the Petén of Guatemala, representatives of Groups I, II, and III occur in sympatry; the absence of haplotypes with intermediate genetic distances, as shown by multimodal mismatch distribution plots, clearly indicates that reproductive barriers actively promote within-group cohesion. Some sylvatic specimens from Belize belong to a different species - likely the basal lineage of the T. dimidiata complex, originated ~8.25 Mya. The evidence presented here strongly supports the proposition that T. dimidiata is a complex of five cryptic species (Groups I-IV plus T. hegneri) that play different roles as vectors of Chagas disease in the region.

Show MeSH
Related in: MedlinePlus