Contrasting patterns of genetic structure and disequilibrium in populations of a stone-cased caddisfly (Tasimiidae) from northern and southern Australia

2008 ◽  
Vol 59 (3) ◽  
pp. 235 ◽  
Author(s):  
Alicia Slater Schultheis ◽  
Richard Marchant ◽  
Jane Margaret Hughes
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Adult Emergence ◽  
Conclusive Evidence ◽  
Emergence Patterns ◽  
Freshwater Invertebrate ◽  
Gene Coi ◽  
Hardy Weinberg Equilibrium ◽  
New Recruits ◽  
Genetic Patchiness

In marine and freshwater invertebrate populations, microscale genetic differentiation or ‘genetic patchiness’ is thought to result from variation in the abundance and genetic composition of new recruits at a particular location. In the present study, the role of the adult emergence patterns in genetic patchiness was examined using mtDNA and two microsatellite loci to compare patterns of genetic differentiation in asynchronously (subtropical) and synchronously emerging (temperate) populations of the stone-cased caddisfly Tasimia palpata. A 550 base pair region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was sequenced in at least 14 individuals from each population. Genetic structure was detected only at the reach scale in the subtropical populations and no genetic differentiation was detected in temperate populations. There were more deviations from Hardy–Weinberg equilibrium (HWE) in subtropical populations than in temperate populations where 44% and 12.5%, respectively, of tests for deviations from HWE were significant. Although distinct patterns of genetic structure and deviations from HWE were observed in the subtropical and temperate populations of T. palpata, no conclusive evidence was found to suggest that the differences are caused by differences in emergence patterns. We hypothesise that genetic patchiness must be caused by post-recruitment processes, most likely the preservation of oviposition ‘hotspots’ in subtropical streams.

scholarly journals Pesticides and the evolution of the genetic structure of Anopheles coluzzii populations in some localities in Benin (West Africa)

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Arsène Jacques Y. H. Fassinou ◽  
Come Z. Koukpo ◽  
Razaki A. Ossè ◽  
Fiacre R. Agossa ◽  
Roseric Azondékon ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Anopheles Coluzzii ◽  
Natural Habitats ◽  
Chi Square ◽  
Agroecological Zones ◽  
Chi Square Test ◽  
Hardy Weinberg Equilibrium ◽  
Study Sites ◽  
Homozygous Resistant

Abstract Background Changes in the natural habitats of insect groups are determined the genetic polymorphisms between individuals. The objective of this study was to establish the genetic structure of the Anopheles coluzzii populations in four localities of Benin. Methods Insecticide surveys and larval sampling were conducted on 4 study localities, including Cotonou, Ketou, Zagnanado, and Sô-Ava. Molecular characterizations were performed on the Anopheles mosquitoes collected with the allelic and genotypic frequencies of kdr gene determined. The multiple comparison Chi square test for proportions was performed with R version 3.3.3. Next, the observed heterozygosity, expected heterozygosity, and indices of fixation, and genetic differentiation were estimated. Finally, the Hardy–Weinberg equilibrium (EHW) was determined to assess whether panmixia exists in the different populations of mosquitoes of the agroecological zones under study. Results Carbamates, pyrethroids, organophosphorus and organochlorines use have been reported in all localities except Sô-Ava. Anopheles coluzzii was strongly represented across all study localities. The L1014F allele was observed in the localities of Kétou, Cotonou and Zagnanado. Likewise, insecticide selection pressure of homozygous resistant individuals (L1014F/L1014F) was significantly higher in Kétou, Cotonou and Zagnanado (p value < 0.05). Surprisingly in Sô-Ava, a relatively high frequency of the L1014F allele despite the reported absence of pesticide use was observed. All mosquito populations were found to be deficient in heterozygosity across the study sites (FIS< 0). No genetic differentiation (FST< 0) was observed in the localities of Zagnanado and Kétou. Conclusion The survey on the use of insecticides showed that insecticide selection pressures differ across the investigated localities. It would be desirable to rotate or apply formulations of combined products with different modes of action. Doing so would enable a better management of resistant homozygous individuals, and mitigate the resistance effect of commonly used insecticides.

Genetic structure of marginal populations of white spruce (Piceaglauca) at its northern limit of distribution in Nouveau-Québec

1989 ◽  
Vol 19 (11) ◽  
pp. 1371-1379 ◽  
Author(s):  
Monique Tremblay ◽  
Jean-Pierre Simon
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Geographic Distance ◽  
White Spruce ◽  
Gene Exchange ◽  
Northern Limit ◽  
Marginal Populations ◽  
Subarctic Region ◽  
Hardy Weinberg Equilibrium ◽  
Or Gene

The genetic structure of six marginal populations of white spruce (Piceaglauca (Moench) Voss) located at Richmond Gulf in the subarctic region of Nouveau-Québec, and one southern population located at Kuujjuaraapik (Poste-de-la-Baleine) were analyzed by acrylamide gel electrophoresis for seven enzyme systems. The analysis of 27 loci disclosed an average polymorphism of 76.2% and a level of heterozygosity of 0.319. Data based on Wright's; statistics: indicated a deficiency of heterozygotes for 60% of the loci, as calculated from the Hardy–Weinberg equilibrium. These results, coupled with the very low percentage of filled seeds in cones of all populations, suggest that a certain level of inbreeding or gene exchange among near-neighbour relatives influences the genetic structure of these populations. The genetic differentiation among populations is relatively high for a conifer [Formula: see text] and is not correlated with geographic distance. The age of trees, covering a period of 400 years affected by climatic changes, does not contribute to the genetic differentiation of the populations.

scholarly journals Patterns of genetic variation in leading-edge populations of Quercus robur: genetic patchiness due to family clusters

2020 ◽  
Vol 16 (5) ◽  
Author(s):  
Pekka Vakkari ◽  
Mari Rusanen ◽  
Juha Heikkinen ◽  
Tea Huotari ◽  
Katri Kärkkäinen
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Quercus Robur ◽  
Spatial Genetic Structure ◽  
Medium Size ◽  
Pedunculate Oak ◽  
Genetic Structures ◽  
Genetic Patchiness

Abstract The genetic structure of populations at the edge of species distribution is important for species adaptation to environmental changes. Small populations may experience non-random mating and differentiation due to genetic drift but larger populations, too, may have low effective size, e.g., due to the within-population structure. We studied spatial population structure of pedunculate oak, Quercus robur, at the northern edge of the species’ global distribution, where oak populations are experiencing rapid climatic and anthropogenic changes. Using 12 microsatellite markers, we analyzed genetic differentiation of seven small to medium size populations (census sizes 57–305 reproducing trees) and four populations for within-population genetic structures. Genetic differentiation among seven populations was low (Fst = 0.07). We found a strong spatial genetic structure in each of the four populations. Spatial autocorrelation was significant in all populations and its intensity (Sp) was higher than those reported in more southern oak populations. Significant genetic patchiness was revealed by Bayesian structuring and a high amount of spatially aggregated full and half sibs was detected by sibship reconstruction. Meta-analysis of isoenzyme and SSR data extracted from the (GD)2 database suggested northwards decreasing trend in the expected heterozygosity and an effective number of alleles, thus supporting the central-marginal hypothesis in oak populations. We suggest that the fragmented distribution and location of Finnish pedunculate oak populations at the species’ northern margin facilitate the formation of within-population genetic structures. Information on the existence of spatial genetic structures can help conservation managers to design gene conservation activities and to avoid too strong family structures in the sampling of seeds and cuttings for afforestation and tree improvement purposes.

scholarly journals The Genetic Diversity and Population Genetic Structure of the Red Panda, Ailurus fulgens, in Zoos in China

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1008
Author(s):  
Yun-fang Xiu ◽  
Cheng-Chi Liu ◽  
Su-hui Xu ◽  
Chen-Si Lin ◽  
Chin-Cheng Chou
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Management Program ◽  
High Genetic Diversity ◽  
Red Panda ◽  
Hardy Weinberg Equilibrium ◽  
Ailurus Fulgens

In China, red pandas (Ailurus fulgens) have been raised in zoos for 60 years. It is very important to understand the genetic diversity and population genetic structure of the captive red pandas. Based on 19 microsatellite loci, we investigated genetic diversity and population genetic structure of 116 captive red pandas, with samples taken from 11 captive populations in China. Our results revealed a high genetic diversity among the populations, with mean allelic richness varying from 3.505 (Beijing) to 4.026 (Mianning), and expected heterozygosities varying from 0.631 (Huangshan) to 0.782 (Wenling). In particular, significant deviation from Hardy–Weinberg equilibrium was found in populations of Fuzhou and Jiangsu. The genetic differentiation index across all populations was 0.055, indicating a significant genetic differentiation among the 11 populations. These populations could be divided into three genetic clusters using a microsatellite-based Bayesian clustering analysis, which were consistent with the clustering results of wild populations. We conclude that the genetic diversity among captive red pandas is as high as that of the wild population. More attention should be paid to develop a proper and scientifically-based management program to avoid inbreeding and maintain a high genetic diversity in captive red pandas.

Population Genetic Structure and Breeding Pattern of Cimex hemipterus (F.) (Hemiptera: Cimicidae) in Malaysia

2019 ◽  
Vol 56 (4) ◽  
pp. 942-952 ◽  
Author(s):  
Siti Nor Ain Seri Masran ◽  
Abdul Hafiz Ab Majid
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Phylogenetic Trees ◽  
Information Criteria ◽  
Bed Bug ◽  
Cimex Hemipterus ◽  
Geographical Populations ◽  
Genomic Studies ◽  
Scoring Errors ◽  
Hardy Weinberg Equilibrium

Abstract The surge in tropical bed bug Cimex hemipterus (Fabricius) (Hemiptera: Cimicidae) infestations has led to an increase in genomic studies. In this study, the population genetics and breeding patterns of 22 Malaysian populations were analyzed, including genetic differentiation and genetic distance. For seven microsatellite loci, the number of alleles varied from 6 to 14. The allelels per loci contrasted sharply between the overall population and within the populations. The average observed and expected heterozygosity was 0.280 and 0.828 for the overall population and 0.281 and 0.657 among the populations, respectively. Based on polymorphic information criteria, the markers with a value >0.5 were highly polymorphic. In the Hardy–Weinberg equilibrium, the loci of Ch 09ttn, Ch 01dn, and Ch 13dn of the overall population showed signs of a null allele. The stutter peaks caused no scoring errors; large allele dropouts were not detected for any loci; and a correlation imbalance was not indicated. The genetic differentiation among populations was moderate, with a coefficient of genetic differentiation (FST) of 0.144. The bed bug populations showed strong inbreeding, with highly positive coefficients of inbreeding (FIS). The molecular variation attributed to inbreeding was 83% within the populations, compared with 17% among the populations. The admixture individuals in STRUCTURE and neighbor-joining phylogenetic trees also indicated weak genetic structure in the geographical populations, suggesting moderate gene flows between populations. Thus, moderately active dispersion and human-mediated transport shaped the genetic structure of C. hemipterus populations in Malaysia.

Pupal Development and Adult Emergence Patterns of the Mexican Rice Borer (Lepidoptera: Pyralidae)

1995 ◽  
Vol 24 (1) ◽  
pp. 76-87 ◽  
Author(s):  
D. W. Spurgeon ◽  
P. D. Lingren ◽  
J. R. Raulston ◽  
T. N. Shaver
Keyword(s):  
Adult Emergence ◽  
Pupal Development ◽  
Emergence Patterns ◽  
Lepidoptera Pyralidae ◽  
Mexican Rice Borer

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

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.

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

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0240743
Author(s):  
Maurice Marcel Sandeu ◽  
Charles Mulamba ◽  
Gareth D. Weedall ◽  
Charles S. Wondji
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Anopheles Funestus ◽  
Metabolic Resistance ◽  
Transcription Analysis ◽  
Genome Wide

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.

scholarly journals Population Genetic Structure of Rhizoctonia oryzae-sativae from Rice in Latin America and Its Adaptive Potential to Emerge as a Pathogen on Urochloa Pastures

2017 ◽  
Vol 107 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Danilo A. dos Santos Pereira ◽  
Paulo C. Ceresini ◽  
Vanina L. Castroagudín ◽  
Lina M. Ramos-Molina ◽  
Edisson Chavarro-Mesa ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Reproductive System ◽  
Population Genetic ◽  
Upland Rice ◽  
Adaptive Potential ◽  
Rhizoctonia Oryzae ◽  
Hardy Weinberg Equilibrium ◽  
Two Populations ◽  
Brazilian Populations

The fungus Rhizoctonia oryzae-sativae is an important pathogen that causes the aggregated sheath spot disease on rice. In this study, we investigated the genetic structure of rice-adapted populations of R. oryzae-sativae sampled from traditional rice-cropping areas from the Paraíba Valley, São Paulo, Brazil, and from Meta, in the Colombian Llanos, in South America. We used five microsatellite loci to measure population differentiation and infer the pathogen’s reproductive system. Gene flow was detected among the three populations of R. oryzae-sativae from lowland rice in Brazil and Colombia. In contrast, a lack of gene flow was observed between the lowland and the upland rice populations of the pathogen. Evidence of sexual reproduction including low clonality, Hardy-Weinberg equilibrium within loci and gametic equilibrium between loci, indicated the predominance of a mixed reproductive system in all populations. In addition, we assessed the adaptive potential of the Brazilian populations of R. oryzae-sativae to emerge as a pathogen to Urochloa spp. (signalgrass) based on greenhouse aggressiveness assays. The Brazilian populations of R. oryzae-sativae were probably only incipiently adapted as a pathogen to Urochloa spp. Comparison between RST and QST showed the predominance of diversifying selection in the divergence between the two populations of R. oryzae-sativae from Brazil.

Seasonal emergence patterns of Sitodiplosis mosellana (Diptera: Cecidomyiidae) in the Peace River region, Alberta, Canada

2021 ◽  
pp. 1-15
Author(s):  
Amanda Jorgensen ◽  
Maya L. Evenden ◽  
Owen Olfert ◽  
Jennifer Otani
Keyword(s):  
Adult Emergence ◽  
Geographic Region ◽  
Invasive Pest ◽  
Phenological Model ◽  
Sitodiplosis Mosellana ◽  
Peace River ◽  
Wheat Midge ◽  
Emergence Patterns ◽  
River Region ◽  
Accumulated Rainfall

Abstract Wheat midge, Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae), is an invasive pest of wheat, Triticum spp. (Poaceae), in North America and is found in all wheat-growing regions of the world. Wheat midge biology, particularly post-diapause emergence of adults, varies with geographic region. The biology of wheat midge has not previously been examined in the northernmost area of its range in Canada – the Peace River region of Alberta. Wheat midge adult emergence was compared in situ to two phenological models of wheat midge emergence developed in other geographic regions. In-field adult emergence did not match the published phenological models. In the Peace River region, adults emerged later than are predicted by both models and precision for both models was low. With the Saskatchewan model, accumulated rainfall that was more than 110 mm in May and early June delayed emergence, whereas accumulated rainfall that was less than 43 mm during that period caused earlier than predicted emergence. Multiple peaks of wheat midge emergence, up to 20 days apart, were observed at some sites, supporting the Jacquemin model depicting “waves” of emergence. Including differences in soil temperature accumulation related to precipitation and optimising the model temperature thresholds would improve accuracy of the current Canadian phenological model in the Peace River region.

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