A differential expression of pyrethroid resistance genes in the malaria vector Anopheles funestus across Uganda is associated with patterns of gene flow

Background Insecticide resistance is challenging the effectiveness of insecticide-based control interventions to reduce malaria burden in Africa. Understanding the molecular basis of insecticides resistance and patterns of gene flow in major malaria vectors such as Anopheles funestus are important steps for designing effective resistance management strategies. Here, we investigated the association between patterns of genetic structure and expression profiles of genes involved in the pyrethroid resistance in An. funestus across Uganda and neighboring Kenya. Methods Blood-fed mosquitoes An. funestus were collected across the four localities in Uganda and neighboring Kenya. A Microarray-based genome-wide transcription analysis was performed to identify the set of genes associated with permethrin resistance. 17 microsatellites markers were genotyped and used to establish patterns of genetic differentiation. Results Microarray-based genome-wide transcription profiling of pyrethroid resistance in four locations across Uganda (Arua, Bulambuli, Lira, and Tororo) and Kenya (Kisumu) revealed that resistance was mainly driven by metabolic resistance. The most commonly up-regulated genes in pyrethroid resistance mosquitoes include cytochrome P450s (CYP9K1, CYP6M7, CYP4H18, CYP4H17, CYP4C36). However, expression levels of key genes vary geographically such as the P450 CYP6M7 [Fold-change (FC) = 115.8 (Arua) vs 24.05 (Tororo) and 16.9 (Kisumu)]. In addition, several genes from other families were also over-expressed including Glutathione S-transferases (GSTs), carboxylesterases, trypsin, glycogenin, and nucleotide binding protein which probably contribute to insecticide resistance across Uganda and Kenya. Genotyping of 17 microsatellite loci in the five locations provided evidence that a geographical shift in the resistance mechanisms could be associated with patterns of population structure throughout East Africa. Genetic and population structure analyses indicated significant genetic differentiation between Arua and other localities (FST>0.03) and revealed a barrier to gene flow between Arua and other areas, possibly associated with Rift Valley. Conclusion The correlation between patterns of genetic structure and variation in gene expression could be used to inform future interventions especially as new insecticides are gradually introduced.

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Restriction to gene flow is associated with changes in the molecular basis of pyrethroid resistance in the malaria vector Anopheles funestus

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1615458114 ◽

2016 ◽

Vol 114 (2) ◽

pp. 286-291 ◽

Cited By ~ 18

Author(s):

Kayla G. Barnes ◽

Helen Irving ◽

Martin Chiumia ◽

Themba Mzilahowa ◽

Michael Coleman ◽

...

Keyword(s):

Gene Flow ◽

Molecular Basis ◽

Pyrethroid Resistance ◽

Anopheles Funestus ◽

Polymorphism Analysis ◽

Significant Shift ◽

Transcription Analysis ◽

Genome Wide ◽

A Genome ◽

African Populations

Resistance to pyrethroids, the sole insecticide class recommended for treating bed nets, threatens the control of major malaria vectors, including Anopheles funestus. Effective management of resistance requires an understanding of the dynamics and mechanisms driving resistance. Here, using genome-wide transcription and genetic diversity analyses, we show that a shift in the molecular basis of pyrethroid resistance in southern African populations of this species is associated with a restricted gene flow. Across the most highly endemic and densely populated regions in Malawi, An. funestus is resistant to pyrethroids, carbamates, and organochlorides. Genome-wide microarray-based transcription analysis identified overexpression of cytochrome P450 genes as the main mechanism driving this resistance. The most up-regulated genes include cytochrome P450s (CYP) CYP6P9a, CYP6P9b and CYP6M7. However, a significant shift in the overexpression profile of these genes was detected across a south/north transect, with CYP6P9a and CYP6P9b more highly overexpressed in the southern resistance front and CYP6M7 predominant in the northern front. A genome-wide genetic structure analysis of southern African populations of An. funestus from Zambia, Malawi, and Mozambique revealed a restriction of gene flow between populations, in line with the geographical variation observed in the transcriptomic analysis. Genetic polymorphism analysis of the three key resistance genes, CYP6P9a, CYP6P9b, and CYP6M7, support barriers to gene flow that are shaping the underlying molecular basis of pyrethroid resistance across southern Africa. This barrier to gene flow is likely to impact the design and implementation of resistance management strategies in the region.

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Genomic differentiation in an endemic Philippine genus (Aves: Sarcophanops) due to geographic isolation on recently disassociated islands

10.7287/peerj.preprints.27546v1 ◽

2019 ◽

Author(s):

Luke C Campillo ◽

Joseph D. Manthey ◽

Robert C. Thomson ◽

Peter A. Hosner ◽

Robert G. Moyle

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Genetic Differentiation ◽

Deep Structure ◽

Island Population ◽

Geographic Isolation ◽

Recent Period ◽

Genetic Sampling ◽

Genome Wide ◽

Species Analysis

Phylogeographic studies of Philippine vertebrates have demonstrated that genetic variation is broadly partitioned by Pleistocene island aggregation. Contemporary island discontinuity is expected to influence genetic differentiation, but remains relatively undocumented perhaps because the current episode of island isolation started relatively recently. We investigated inter- and intra-island population structure in a Philippine endemic bird genus (Sarcophanops) to determine if genetic differentiation has evolved during the recent period of isolation. We sequenced thousands of genome-wide RAD markers from throughout the Mindanao group to assess fine-scale genetic structure across islands. Specifically, we investigated patterns of gene flow and connectivity within and between taxonomic and geographic bounds. A previous assessment of mitochondrial DNA detected deep structure between Sarcophanops samarensis and sister species, S. steerii, but was insufficient to detect differentiation within either species. Analysis of RAD markers, however, revealed structure within S. samarensis between the islands of Samar/Leyte and Bohol. This genetic differentiation likely demonstrates an effect of recent geographic isolation (post-LGM) on the genetic structure of Philippine avifauna. We suggest that the general lack of evidence for differentiation between recently isolated islands is a failure to detect subtle population structure due to past genetic sampling constraints, rather than the absence of such structure.

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CYP6P9-Driven Signatures of Selective Sweep of Metabolic Resistance to Pyrethroids in the Malaria Vector Anopheles funestus Reveal Contemporary Barriers to Gene Flow

Genes ◽

10.3390/genes11111314 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1314

Author(s):

Delia Doreen Djuicy ◽

Jack Hearn ◽

Magellan Tchouakui ◽

Murielle J. Wondji ◽

Helen Irving ◽

...

Keyword(s):

Gene Flow ◽

Selective Sweep ◽

Pyrethroid Resistance ◽

Resistance Mechanism ◽

Anopheles Funestus ◽

Central Africa ◽

Eastern Africa ◽

Malaria Vectors ◽

Metabolic Resistance ◽

Diversity Pattern

Pyrethroid resistance in major malaria vectors such as Anopheles funestus threatens malaria control efforts in Africa. Cytochrome P450-mediated metabolic resistance is best understood for CYP6P9 genes in southern Africa in An. funestus. However, we do not know if this resistance mechanism is spreading across Africa and how it relates to broader patterns of gene flow across the continent. Nucleotide diversity of the CYP6P9a gene and the diversity pattern of five gene fragments spanning a region of 120 kb around the CYP6P9a gene were surveyed in mosquitoes from southern, eastern and central Africa. These analyses revealed that a Cyp6P9a resistance-associated allele has swept through southern and eastern Africa and is now fixed in these regions. A similar diversity profile was observed when analysing genomic regions located 34 kb upstream to 86 kb downstream of the CYP6P9a locus, concordant with a selective sweep throughout the rp1 locus. We identify reduced gene flow between southern/eastern Africa and central Africa, which we hypothesise is due to the Great Rift Valley. These potential barriers to gene flow are likely to prevent or slow the spread of CYP6P9-based resistance mechanism to other parts of Africa and would to be considered in future vector control interventions such as gene drive.

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Genomic differentiation in an endemic Philippine genus (Aves: Sarcophanops) due to geographic isolation on recently disassociated islands

10.7287/peerj.preprints.27546 ◽

2019 ◽

Author(s):

Luke Campillo ◽

Joseph D. Manthey ◽

Robert C. Thomson ◽

Peter A. Hosner ◽

Robert G. Moyle

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Genetic Differentiation ◽

Deep Structure ◽

Island Population ◽

Geographic Isolation ◽

Recent Period ◽

Genetic Sampling ◽

Genome Wide ◽

Species Analysis

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Genome-wide gene expression profiling reveals that cuticle alterations and P450 detoxification are associated with pyrethroid resistance in Anopheles arabiensis populations from Ethiopia

10.1101/451336 ◽

2018 ◽

Author(s):

Eba Alemayehu Simma ◽

Wannes Dermauw ◽

Vasileia Balabanidou ◽

Simon Snoeck ◽

Astrid Bryon ◽

...

Keyword(s):

Insecticide Resistance ◽

Anopheles Arabiensis ◽

Pyrethroid Resistance ◽

Resistance Mutation ◽

Resistance Mechanisms ◽

Target Site ◽

Malaria Vectors ◽

Metabolic Resistance ◽

Genome Wide ◽

Target Site Resistance

AbstractBACKGROUNDVector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although a L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance and biochemical studies indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations (Tolay, Asendabo, Chewaka) and two susceptible strains (Sekoru and Mozambique).RESULTSBoth RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance, although this did not translate in increased thickness of the procuticle.CONCLUSIONOur transcriptome sequencing of deltamethrin/DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and pave the way for further investigation of the role of cuticle composition in resistance.

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Genomic differentiation in an endemic Philippine genus (Aves: Sarcophanops) owing to geographical isolation on recently disassociated islands

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blaa143 ◽

2020 ◽

Vol 131 (4) ◽

pp. 814-821

Author(s):

Luke C Campillo ◽

Joseph D Manthey ◽

Robert C Thomson ◽

Peter A Hosner ◽

Robert G Moyle

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Genetic Differentiation ◽

Deep Structure ◽

Island Population ◽

Geographical Isolation ◽

Isolated Populations ◽

Genetic Sampling ◽

Genome Wide ◽

Species Analysis

Abstract Phylogeographical studies of Philippine vertebrates have demonstrated that genetic variation is broadly partitioned by Pleistocene island aggregation. Contemporary island discontinuity is expected to influence genetic differentiation but remains relatively undocumented, perhaps because the current episode of island isolation started in relatively recent times. We investigated inter- and intra-island population structure in a Philippine endemic bird genus (Sarcophanops) to determine whether genetic differentiation has evolved during the recent period of isolation. We sequenced thousands of genome-wide restriction site associated DNA (RAD) markers from throughout the Mindanao group to assess fine-scale genetic structure across islands. Specifically, we investigated patterns of gene flow and connectivity within and between taxonomic and geographical bounds. A previous assessment of mitochondrial DNA detected deep structure between Sarcophanops samarensis and a sister species, Sarcophanops steerii, but was insufficient to detect differentiation within either species. Analysis of RAD markers, however, revealed structure within S. samarensis between the islands of Samar/Leyte and Bohol. This genetic differentiation probably demonstrates an effect of recent geographical isolation (after the Last Glacial Maximum) on the genetic structure of Philippine avifauna. We suggest that the general lack of evidence for differentiation between recently isolated populations is a failure to detect subtle population structure owing to past genetic sampling constraints, rather than the absence of such structure.

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Genetic diversity and population structure of Korean alder (Alnus japonica; Betulaceae)

Canadian Journal of Forest Research ◽

10.1139/x99-067 ◽

1999 ◽

Vol 29 (9) ◽

pp. 1311-1316 ◽

Cited By ~ 9

Author(s):

Man Kyu Huh

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Gene Flow ◽

Genetic Structure ◽

Genetic Differentiation ◽

Population Genetic ◽

Alnus Japonica ◽

Alnus Crispa ◽

The Mean ◽

Fixation Indices

The genetic diversity and population genetic structure of Alnus japonica (Thunb.) Steudel in Korea were studied and compared with those of alder from Canada. Nineteen of the 25 loci studied (76.0%) showed detectable polymorphism. The mean genetic diversity within populations was 0.207, which was higher than that for two Canadian alder species (Alnus rugosa (Du Roi) Spreng. and Alnus crispa (Ait.) Pursh). Analysis of fixation indices, calculated for all polymorphic loci in each population, showed a substantial deficiency of heterozygotes relative to Hardy-Weinberg expectations. The mean population differentiation value of A. japonica in Korea (GST = 0.095) is similar to those of A. rugosa in Canada (GST = 0.052). These low values of GST in two countries, reflecting little spatial genetic differentiation, may indicate extensive gene flow (via pollen and (or) seeds) and (or) recent colonization.

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Patterns of spatial genetic structures in Aedes albopictus (Diptera: Culicidae) populations in China

Parasites & Vectors ◽

10.1186/s13071-019-3801-4 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Yong Wei ◽

Jiatian Wang ◽

Zhangyao Song ◽

Yulan He ◽

Zihao Zheng ◽

...

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Gene Flow ◽

Genetic Structure ◽

Genetic Differentiation ◽

Population Genetic ◽

Spatial Genetic Structure ◽

Vector Borne Diseases ◽

Vector Borne ◽

Genetic Structures

Abstract Background The Asian tiger mosquito, Aedes albopictus, is one of the 100 worst invasive species in the world and the vector for several arboviruses including dengue, Zika and chikungunya viruses. Understanding the population spatial genetic structure, migration, and gene flow of vector species is critical to effectively preventing and controlling vector-borne diseases. Little is known about the population structure and genetic differentiation of native Ae. albopictus in China. The aim of this study was to examine the patterns of the spatial genetic structures of native Ae. albopictus populations, and their relationship to dengue incidence, on a large geographical scale. Methods During 2016–2018, adult female Ae. albopictus mosquitoes were collected by human landing catch (HLC) or human-bait sweep-net collections in 34 localities across China. Thirteen microsatellite markers were used to examine the patterns of genetic diversity, population structure, and gene flow among native Ae. albopictus populations. The correlation between population genetic indices and dengue incidence was also examined. Results A total of 153 distinct alleles were identified at the 13 microsatellite loci in the tested populations. All loci were polymorphic, with the number of distinct alleles ranging from eight to sixteen. Genetic parameters such as PIC, heterozygosity, allelic richness and fixation index (FST) revealed highly polymorphic markers, high genetic diversity, and low population genetic differentiation. In addition, Bayesian analysis of population structure showed two distinct genetic groups in southern-western and eastern-central-northern China. The Mantel test indicated a positive correlation between genetic distance and geographical distance (R2 = 0.245, P = 0.01). STRUCTURE analysis, PCoA and GLS interpolation analysis indicated that Ae. albopictus populations in China were regionally clustered. Gene flow and relatedness estimates were generally high between populations. We observed no correlation between population genetic indices of microsatellite loci in Ae. albopictus populations and dengue incidence. Conclusion Strong gene flow probably assisted by human activities inhibited population differentiation and promoted genetic diversity among populations of Ae. albopictus. This may represent a potential risk of rapid spread of mosquito-borne diseases. The spatial genetic structure, coupled with the association between genetic indices and dengue incidence, may have important implications for understanding the epidemiology, prevention, and control of vector-borne diseases.

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Population Genetics and Evolution Analysis Reveal Diversity and Origin of Ammopiptanthus in China.

10.21203/rs.3.rs-779119/v1 ◽

2021 ◽

Author(s):

Guai-qiang Chai ◽

Yizhong Duan ◽

Peipei Jiao ◽

Zhongyu Du ◽

Furen Kang

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Genetic Differentiation ◽

Association Studies ◽

Natural Populations ◽

Principal Component ◽

Nucleotide Polymorphisms ◽

Future Design ◽

Ammopiptanthus Nanus ◽

Genome Wide

Abstract Background：Elucidating and revealing the population genetic structure, genetic diversity and recombination is essential for understanding the evolution and adaptation of species. Ammopiptanthus, which is an endangered survivor from the Tethys in the Tertiary Period, is the only evergreen broadleaf shrub grown in Northwest of China. However, little is known about its genetic diversity and underlying adaptation mechanisms. Results：Here, 111 Ammopiptanthus individuals collected from fifteen natural populations in estern China were analyzed by means of the specific locus amplified fragment sequencing (SLAF-seq). Based on the single nucleotide polymorphisms (SNPs) and insertions and deletions (InDels) detected by SLAF-seq, genetic diversity and markers associated with climate and geographical distribution variables were identified. The results of genetic diversity and genetic differentiation revealed that all fifteen populations showed medium genetic diversity, with PIC values ranging from 0.1648 to 0.3081. AMOVA and Fst indicated that a low genetic differentiation existed among populations. Phylogenetic analysis showed that NX-BG and NMG-DQH of fifteen populations have the highest homology，while the genetic structure analysis revealed that these Ammopiptanthus germplasm accessions were structured primarily along the basis of their geographic collection, and that an extensive admixture occurred in each group. In addition, the genome-wide linkage disequilibrium (LD) and principal component analysis showed that Ammopiptanthus nanus had a more diverse genomic background, and all genetic populations were clearly distinguished, although different degrees of introgression were detected in these groups. Conclusion：Our study could provide guidance to the future design of association studies and the systematic utilization and protection of the genetic variation characterizing the Ammopiptanthus.

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Population Genetics of the Red Rock Lobster, Jasus edwardsii

10.26686/wgtn.16999873.v1 ◽

2021 ◽

Author(s):

◽

Luke Thomas

Keyword(s):

Population Structure ◽

Gene Flow ◽

New Zealand ◽

Genetic Differentiation ◽

Microsatellite Markers ◽

Rocky Reef ◽

Rock Lobster ◽

Wide Range ◽

Jasus Edwardsii ◽

Polymorphic Microsatellite

<p>Understanding patterns of gene flow across a species range is a vital component of an effective fisheries management strategy. The advent of highly polymorphic microsatellite markers has facilitated the detection of fine-scale patterns of genetic differentiation at levels below the resolving power of earlier techniques. This has triggered the wide-spread re-examination of population structure for a number of commercially targeted species. The aims of thesis were to re-investigate patterns of gene flow of the red rock lobster Jasus edwardsii throughout New Zealand and across the Tasman Sea using novel microsatellite markers. Jasus edwardsii is a keystone species of subtidal rocky reef system and supports lucrative export markets in both Australia and New Zealand. Eight highly polymorphic microsatellite markers were developed from 454 sequence data and screened across a Wellington south coast population to obtain basic diversity indices. All loci were polymorphic with the number of alleles per locus ranging from 6-39. Observed and expected heterozygosity ranged from 0.563-0.937 and 0.583-0.961, respectively. There were no significant deviations from Hardy-Weinberg equilibrium following standard Bonferroni corrections. The loci were used in a population analysis of J. edwardsii that spanned 10 degrees of latitude and stretched 3,500 km across the South Pacific. The analysis rejected the null-hypothesis of panmixia based on earlier mDNA analysis and revealed significant population structure (FST=0.011, RST=0.028) at a wide range of scales. Stewart Island was determined to have the highest levels of genetic differentiation of all populations sampled suggesting a high degree of reproductive isolation and self-recruitment. This study also identified high levels of asymmetric gene flow from Australia to New Zealand indicating a historical source-sink relationship between the two countries. Results from the genetic analysis were consistent with results from oceanographic dispersal models and it is likely that the genetic results reflect historical and contemporary patterns of Jasus edwardsii dispersal and recruitment throughout its range.</p>

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