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Lineage divergence detected in the malaria vector Anopheles marajoara (Diptera: Culicidae) in Amazonian Brazil.

McKeon SN, Lehr MA, Wilkerson RC, Ruiz JF, Sallum MA, Lima JB, Povoa MM, Conn JE - Malar. J. (2010)

Bottom Line: COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82%) compared to the more moderate 2.92% detected by the Folmer region.Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that the divergence is recent, and detectable only by the faster evolving mtDNA.Differences in demographic history and climatic changes may have contributed to mtDNA lineage divergence in A. marajoara.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Empire State Plaza, Albany, NY 12201 USA.

ABSTRACT

Background: Cryptic species complexes are common among anophelines. Previous phylogenetic analysis based on the complete mtDNA COI gene sequences detected paraphyly in the Neotropical malaria vector Anopheles marajoara. The "Folmer region" detects a single taxon using a 3% divergence threshold.

Methods: To test the paraphyletic hypothesis and examine the utility of the Folmer region, genealogical trees based on a concatenated (white + 3' COI sequences) dataset and pairwise differentiation of COI fragments were examined. The population structure and demographic history were based on partial COI sequences for 294 individuals from 14 localities in Amazonian Brazil. 109 individuals from 12 localities were sequenced for the nDNA white gene, and 57 individuals from 11 localities were sequenced for the ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS2).

Results: Distinct A. marajoara lineages were detected by combined genealogical analysis and were also supported among COI haplotypes using a median joining network and AMOVA, with time since divergence during the Pleistocene (<100,000 ya). COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82%) compared to the more moderate 2.92% detected by the Folmer region. Lineage 1 was present in all localities, whereas lineage 2 was restricted mainly to the west. Mismatch distributions for both lineages were bimodal, likely due to multiple colonization events and spatial expansion (~798-81,045 ya). There appears to be gene flow within, not between lineages, and a partial barrier was detected near Rio Jari in Amapá state, separating western and eastern populations. In contrast, both nDNA data sets (white gene sequences with or without the retention of the 4th intron, and ITS2 sequences and length) detected a single A. marajoara lineage.

Conclusions: Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that the divergence is recent, and detectable only by the faster evolving mtDNA. A within subgenus threshold of >2% may be more appropriate among sister taxa in cryptic anopheline complexes than the standard 3%. Differences in demographic history and climatic changes may have contributed to mtDNA lineage divergence in A. marajoara.

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Related in: MedlinePlus

Distribution of collection localities of A. marajoara s.l. and A. oryzalimentes. Map of South America indicating the location of the 14 collection localities, lineage distributions and the spatial grouping derived from the SAMOVA analysis. Dotted line corresponds to SAMOVA defined groupings (eastern and western Amazon), based on sequence similarity and geographic distance for A. marajoara lineage 1 among all localities. FCT corresponds to between group variation and FSC indicates variation within groupings.
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Figure 3: Distribution of collection localities of A. marajoara s.l. and A. oryzalimentes. Map of South America indicating the location of the 14 collection localities, lineage distributions and the spatial grouping derived from the SAMOVA analysis. Dotted line corresponds to SAMOVA defined groupings (eastern and western Amazon), based on sequence similarity and geographic distance for A. marajoara lineage 1 among all localities. FCT corresponds to between group variation and FSC indicates variation within groupings.

Mentions: AMOVA indicated that 61.94% (p = 0.0000) of the variance was explained by between-group variation of A. marajoara lineages 1 and 2. SAMOVA analysis, providing resolution for lineage 1 only, defined two groups that correspond to northeastern and western Amazonia, with 61.36% regional variation (Figure 3). Several COI haplotypes were found in both the northeastern and western populations of lineage 1 indicating at least some gene flow across the geographic barrier. High variation, especially between lineages 1 and 2, and between geographic populations in both COI and white genes, is strongly supported by population differentiation statistics, although the GST values were not significantly different (Table 3). Furthermore, the Kt values were much greater for the COI gene (11.9 and 6.96), compared with the white gene (1.0).


Lineage divergence detected in the malaria vector Anopheles marajoara (Diptera: Culicidae) in Amazonian Brazil.

McKeon SN, Lehr MA, Wilkerson RC, Ruiz JF, Sallum MA, Lima JB, Povoa MM, Conn JE - Malar. J. (2010)

Distribution of collection localities of A. marajoara s.l. and A. oryzalimentes. Map of South America indicating the location of the 14 collection localities, lineage distributions and the spatial grouping derived from the SAMOVA analysis. Dotted line corresponds to SAMOVA defined groupings (eastern and western Amazon), based on sequence similarity and geographic distance for A. marajoara lineage 1 among all localities. FCT corresponds to between group variation and FSC indicates variation within groupings.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2959070&req=5

Figure 3: Distribution of collection localities of A. marajoara s.l. and A. oryzalimentes. Map of South America indicating the location of the 14 collection localities, lineage distributions and the spatial grouping derived from the SAMOVA analysis. Dotted line corresponds to SAMOVA defined groupings (eastern and western Amazon), based on sequence similarity and geographic distance for A. marajoara lineage 1 among all localities. FCT corresponds to between group variation and FSC indicates variation within groupings.
Mentions: AMOVA indicated that 61.94% (p = 0.0000) of the variance was explained by between-group variation of A. marajoara lineages 1 and 2. SAMOVA analysis, providing resolution for lineage 1 only, defined two groups that correspond to northeastern and western Amazonia, with 61.36% regional variation (Figure 3). Several COI haplotypes were found in both the northeastern and western populations of lineage 1 indicating at least some gene flow across the geographic barrier. High variation, especially between lineages 1 and 2, and between geographic populations in both COI and white genes, is strongly supported by population differentiation statistics, although the GST values were not significantly different (Table 3). Furthermore, the Kt values were much greater for the COI gene (11.9 and 6.96), compared with the white gene (1.0).

Bottom Line: COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82%) compared to the more moderate 2.92% detected by the Folmer region.Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that the divergence is recent, and detectable only by the faster evolving mtDNA.Differences in demographic history and climatic changes may have contributed to mtDNA lineage divergence in A. marajoara.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Empire State Plaza, Albany, NY 12201 USA.

ABSTRACT

Background: Cryptic species complexes are common among anophelines. Previous phylogenetic analysis based on the complete mtDNA COI gene sequences detected paraphyly in the Neotropical malaria vector Anopheles marajoara. The "Folmer region" detects a single taxon using a 3% divergence threshold.

Methods: To test the paraphyletic hypothesis and examine the utility of the Folmer region, genealogical trees based on a concatenated (white + 3' COI sequences) dataset and pairwise differentiation of COI fragments were examined. The population structure and demographic history were based on partial COI sequences for 294 individuals from 14 localities in Amazonian Brazil. 109 individuals from 12 localities were sequenced for the nDNA white gene, and 57 individuals from 11 localities were sequenced for the ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS2).

Results: Distinct A. marajoara lineages were detected by combined genealogical analysis and were also supported among COI haplotypes using a median joining network and AMOVA, with time since divergence during the Pleistocene (<100,000 ya). COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82%) compared to the more moderate 2.92% detected by the Folmer region. Lineage 1 was present in all localities, whereas lineage 2 was restricted mainly to the west. Mismatch distributions for both lineages were bimodal, likely due to multiple colonization events and spatial expansion (~798-81,045 ya). There appears to be gene flow within, not between lineages, and a partial barrier was detected near Rio Jari in Amapá state, separating western and eastern populations. In contrast, both nDNA data sets (white gene sequences with or without the retention of the 4th intron, and ITS2 sequences and length) detected a single A. marajoara lineage.

Conclusions: Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that the divergence is recent, and detectable only by the faster evolving mtDNA. A within subgenus threshold of >2% may be more appropriate among sister taxa in cryptic anopheline complexes than the standard 3%. Differences in demographic history and climatic changes may have contributed to mtDNA lineage divergence in A. marajoara.

Show MeSH
Related in: MedlinePlus