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Genetic polymorphism at an odorant receptor gene (Or39) among mosquitoes of the Anopheles gambiae complex in Senegal (West Africa).

Arnal A, Kengne P, Brengues C, Dabire KR, Diabate A, Bassene H, Simard F - BMC Res Notes (2014)

Bottom Line: Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein.However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain.Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France. au.arnal@gmail.com.

ABSTRACT

Background: Olfaction plays a significant role in insect behavior during critical steps of their life-cycle, such as host-seeking during foraging or the search for a mate. Here, we explored genetic polymorphism within and divergence between sibling species of the African malaria mosquito, Anopheles gambiae sensu lato in the gene sequence and encoded peptides of an odorant receptor, Or39. This study included sympatric specimens of An. gambiae sensu stricto, An. coluzzii and An. arabiensis sampled together in the village of Dielmo, Senegal.

Results: A 1,601 bp genomic sequence composed of 6 exons and 5 introns was obtained for Or39 from 6-8 mosquitoes in each of the 3 species. DNA sequence analysis revealed a high level of molecular polymorphism (π = 0.0154; Haplotype diversity = 0.867) and high overall genetic differentiation between taxa (Fst > 0.92, P < 0.01). In total, 50 parsimony informative sites were recorded. Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein. Each of the 6 different identified peptides was species-specific and none was shared across species. Most aminoacid changes were located on the intracellular domains of the protein. However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain.

Conclusions: Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.

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Related in: MedlinePlus

Alignment of the predicted amino acid sequences for Or39 odorant receptor of An. gambiae, An. coluzzii and An. arabiensis from Dielmo, Senegal. Reference amino acid sequence for the PEST strain of An. gambiae was obtained from the published cDNA sequence (Accession N° XM_312289.1). Shaded areas represent hydrophobic trans-membrane domains of the protein. Stars denote identity to the reference sequence and dots show amino acid changes. Within-species polymorphisms are bolded and boxed; Polymorphic sites among species are highlighted in reversed fonts.
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Figure 3: Alignment of the predicted amino acid sequences for Or39 odorant receptor of An. gambiae, An. coluzzii and An. arabiensis from Dielmo, Senegal. Reference amino acid sequence for the PEST strain of An. gambiae was obtained from the published cDNA sequence (Accession N° XM_312289.1). Shaded areas represent hydrophobic trans-membrane domains of the protein. Stars denote identity to the reference sequence and dots show amino acid changes. Within-species polymorphisms are bolded and boxed; Polymorphic sites among species are highlighted in reversed fonts.

Mentions: The open reading frame of the 1400 bp cDNA encoded a 407 amino acid sequence for Or39. Throughout the whole dataset, there were 13 non-synonymous replacement mutations resulting in aminoacid changes in the encoded protein. The amino acid sequences obtained from deducted cDNA sequences resulted in 6 distinct peptides: 3 in An. arabiensis, 2 in An. gambiae and a single peptide encoded by An. coluzzii DNA (Figure 3). Note that all peptides identified from wild mosquito specimens were distinct from the protein sequence deducted from the PEST strain DNA. Moreover, each peptide was species-specific and they were not shared across species. There were 4 amino acid changes between An. gambiae and An. coluzzii resulting in a Methionin-to-Valine substitution at position 42, a Serine-to-Threonine substitution at position 116, a Histidine-to-Arginine substitution at position 339 and a Glutamine-to-Glycine substitution at position 343 (Figure 3).


Genetic polymorphism at an odorant receptor gene (Or39) among mosquitoes of the Anopheles gambiae complex in Senegal (West Africa).

Arnal A, Kengne P, Brengues C, Dabire KR, Diabate A, Bassene H, Simard F - BMC Res Notes (2014)

Alignment of the predicted amino acid sequences for Or39 odorant receptor of An. gambiae, An. coluzzii and An. arabiensis from Dielmo, Senegal. Reference amino acid sequence for the PEST strain of An. gambiae was obtained from the published cDNA sequence (Accession N° XM_312289.1). Shaded areas represent hydrophobic trans-membrane domains of the protein. Stars denote identity to the reference sequence and dots show amino acid changes. Within-species polymorphisms are bolded and boxed; Polymorphic sites among species are highlighted in reversed fonts.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4048261&req=5

Figure 3: Alignment of the predicted amino acid sequences for Or39 odorant receptor of An. gambiae, An. coluzzii and An. arabiensis from Dielmo, Senegal. Reference amino acid sequence for the PEST strain of An. gambiae was obtained from the published cDNA sequence (Accession N° XM_312289.1). Shaded areas represent hydrophobic trans-membrane domains of the protein. Stars denote identity to the reference sequence and dots show amino acid changes. Within-species polymorphisms are bolded and boxed; Polymorphic sites among species are highlighted in reversed fonts.
Mentions: The open reading frame of the 1400 bp cDNA encoded a 407 amino acid sequence for Or39. Throughout the whole dataset, there were 13 non-synonymous replacement mutations resulting in aminoacid changes in the encoded protein. The amino acid sequences obtained from deducted cDNA sequences resulted in 6 distinct peptides: 3 in An. arabiensis, 2 in An. gambiae and a single peptide encoded by An. coluzzii DNA (Figure 3). Note that all peptides identified from wild mosquito specimens were distinct from the protein sequence deducted from the PEST strain DNA. Moreover, each peptide was species-specific and they were not shared across species. There were 4 amino acid changes between An. gambiae and An. coluzzii resulting in a Methionin-to-Valine substitution at position 42, a Serine-to-Threonine substitution at position 116, a Histidine-to-Arginine substitution at position 339 and a Glutamine-to-Glycine substitution at position 343 (Figure 3).

Bottom Line: Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein.However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain.Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France. au.arnal@gmail.com.

ABSTRACT

Background: Olfaction plays a significant role in insect behavior during critical steps of their life-cycle, such as host-seeking during foraging or the search for a mate. Here, we explored genetic polymorphism within and divergence between sibling species of the African malaria mosquito, Anopheles gambiae sensu lato in the gene sequence and encoded peptides of an odorant receptor, Or39. This study included sympatric specimens of An. gambiae sensu stricto, An. coluzzii and An. arabiensis sampled together in the village of Dielmo, Senegal.

Results: A 1,601 bp genomic sequence composed of 6 exons and 5 introns was obtained for Or39 from 6-8 mosquitoes in each of the 3 species. DNA sequence analysis revealed a high level of molecular polymorphism (π = 0.0154; Haplotype diversity = 0.867) and high overall genetic differentiation between taxa (Fst > 0.92, P < 0.01). In total, 50 parsimony informative sites were recorded. Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein. Each of the 6 different identified peptides was species-specific and none was shared across species. Most aminoacid changes were located on the intracellular domains of the protein. However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain.

Conclusions: Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.

Show MeSH
Related in: MedlinePlus