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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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A Neighbor-Joining tree based on molecular polymorphism in intron and exon sequences (1,601 bp) of the Or39 odorant receptor gene among mosquito specimens collected in the locality of Dielmo, Senegal. Values at the nodes are bootstrap values [36].
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Figure 2: A Neighbor-Joining tree based on molecular polymorphism in intron and exon sequences (1,601 bp) of the Or39 odorant receptor gene among mosquito specimens collected in the locality of Dielmo, Senegal. Values at the nodes are bootstrap values [36].

Mentions: Figure 2 shows a Neighbour-Joining tree constructed with Kimura-2-parameter genetic distances, retained as the best model based on the Bayesian Information Criterion (BIC) scores used in MEGA6, between the 10 haplotypes shown in Figure 1. Specimens segregated unambiguously into the 3 known taxa, An. gambiae, An. coluzzii and An. arabiensis. Note that the PEST strain sequence maps as expected, in between the An. gambiae and An. coluzzii clusters. The PEST genome is indeed known to be a composite genome of the two cryptic species.


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)

A Neighbor-Joining tree based on molecular polymorphism in intron and exon sequences (1,601 bp) of the Or39 odorant receptor gene among mosquito specimens collected in the locality of Dielmo, Senegal. Values at the nodes are bootstrap values [36].
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: A Neighbor-Joining tree based on molecular polymorphism in intron and exon sequences (1,601 bp) of the Or39 odorant receptor gene among mosquito specimens collected in the locality of Dielmo, Senegal. Values at the nodes are bootstrap values [36].
Mentions: Figure 2 shows a Neighbour-Joining tree constructed with Kimura-2-parameter genetic distances, retained as the best model based on the Bayesian Information Criterion (BIC) scores used in MEGA6, between the 10 haplotypes shown in Figure 1. Specimens segregated unambiguously into the 3 known taxa, An. gambiae, An. coluzzii and An. arabiensis. Note that the PEST strain sequence maps as expected, in between the An. gambiae and An. coluzzii clusters. The PEST genome is indeed known to be a composite genome of the two cryptic species.

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