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.

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.

scholarly journals A strategic sampling design revealed the local genetic structure of cold-water fluvial sculpin: a focus on groundwater-dependent water temperature heterogeneity

2021 ◽  
Author(s):  
Souta Nakajima ◽  
Masanao Sueyoshi ◽  
Shun K. Hirota ◽  
Nobuo Ishiyama ◽  
Ayumi Matsuo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Low Temperature ◽  
Genetic Differentiation ◽  
Water Temperature ◽  
Sampling Design ◽  
Cold Water ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Sampling Strategy ◽  
Genotyping By Sequencing

A key piece of information for ecosystem management is the relationship between the environment and population genetic structure. However, it is difficult to clearly quantify the effects of environmental factors on genetic differentiation because of spatial autocorrelation and analytical problems. In this study, we focused on stream ecosystems and the environmental heterogeneity caused by groundwater and constructed a sampling design in which geographic distance and environmental differences are not correlated. Using multiplexed ISSR genotyping by sequencing (MIG-seq) method, a fine-scale population genetics study was conducted in fluvial sculpin Cottus nozawae, for which summer water temperature is the determinant factor in distribution and survival. There was a clear genetic structure in the watershed. Although a significant isolation-by-distance pattern was detected in the watershed, there was no association between genetic differentiation and water temperature. Instead, asymmetric gene flow from relatively low-temperature streams to high-temperature streams was detected, indicating the importance of low-temperature streams and continuous habitats. The groundwater-focused sampling strategy yielded unexpected results and provided important insights for conservation.

scholarly journals Identifying environmental factors associated with the genetic structure of the New Zealand scallop: linking seascape genetics and ecophysiological tolerance

2015 ◽  
Vol 73 (7) ◽  
pp. 1925-1934 ◽  
Author(s):  
Catarina N. S. Silva ◽  
Jonathan P. A. Gardner
Keyword(s):  
Genetic Variation ◽  
New Zealand ◽  
Genetic Structure ◽  
Environmental Factors ◽  
Genetic Differentiation ◽  
Environmental Variables ◽  
Evolutionary Dynamics ◽  
Geographic Distance ◽  
Suspended Particulate Matter Concentration ◽  
Seascape Genetics

Abstract Understanding the processes responsible for shaping the spatial genetic patterns of species is critical for predicting evolutionary dynamics and defining significant evolutionary and/or management units. Here, we investigated the potential role of environmental factors in shaping the genetic structure of the endemic New Zealand scallop Pecten novaezelandiae using a seascape genetics approach. For this, we assayed genetic variation at 12 microsatellite markers in 952 individuals collected from 14 sites throughout New Zealand, and used data for 9 site-specific environmental variables (3 geospatial and 6 environmental variables). Our results indicate that a combination of environmental factors may be contributing to the observed patterns of genetic differentiation, but in particular, freshwater discharge and suspended particulate matter concentration were identified as being important. Environmental variation in these parameters may be acting as a barrier to gene flow. In terms of their ecophysiology, scallops are not particularly tolerant of high concentrations of either freshwater input or suspended sediment, making the identification of an association between these environmental variables and genetic variation particularly relevant across the full distributional range of this species. Although geographic distance between populations was also an important variable explaining the genetic variation among populations, it appears that levels of genetic differentiation are not a simple function of interpopulation distance. This study has identified previously unknown environmental factors that may be acting on the genetic structure of the New Zealand scallop and highlights the utility of seascape genetic studies to better understand the processes shaping the genetic structure of organisms.

scholarly journals Fine-scale genetic structure of the overwintering Chilo suppressalis in the typical bivoltine areas of northern China

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243999
Author(s):  
Ke-Xin Zhu ◽  
Shan Jiang ◽  
Lei Han ◽  
Ming-Ming Wang ◽  
Xing-Ya Wang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Genetic Relationships ◽  
Management Strategies ◽  
Geographic Distance ◽  
Northern China ◽  
Economic Losses ◽  
Chilo Suppressalis

The rice stem borer (RSB), Chilo suppressalis (Lepidoptera: Pyralidae), is an important agricultural pest that has caused serious economic losses in the major rice-producing areas of China. To effectively control this pest, we investigated the genetic diversity, genetic differentiation and genetic structure of 16 overwintering populations in the typical bivoltine areas of northern China based on 12 nuclear microsatellite loci. Moderate levels of genetic diversity and genetic differentiation among the studied populations were detected. Neighbour-joining dendrograms, Bayesian clustering and principal coordinate analysis (PCoA) consistently divided these populations into three genetic clades: western, eastern and northern/central. Isolation by distance (IBD) and spatial autocorrelation analyses demonstrated no correlation between genetic distance and geographic distance. Bottleneck analysis illustrated that RSB populations had not undergone severe bottleneck effects in these regions. Accordingly, our results provide new insights into the genetic relationships of overwintering RSB populations and thus contribute to developing effective management strategies for this pest.

Structure et variabilité génétique de populations d'épinette noire (Piceamariana (Mill.) B.S.P.) dans la zone hémiarctique du Nouveau-Québec

1987 ◽  
Vol 17 (9) ◽  
pp. 1006-1012 ◽  
Author(s):  
Mireille Desponts ◽  
Jean-Pierre Simon
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Variability ◽  
Gel Electrophoresis ◽  
Black Spruce ◽  
Geographic Isolation ◽  
Marginal Populations ◽  
Isolated Populations ◽  
Subarctic Region ◽  
Enzyme Systems

The genetic structure of five populations of black spruce located at l'Eau Claire Lake, in the subarctic region of Nouveau-Québec, were analysed by acrylamide gel electrophoresis of seven enzyme systems. The analysis of 25 loci disclosed an average polymorphism of 0.80 and a level of heterozygosity of 0.351. Results indicate that there is no loss of genetic variability in these marginal populations that could be attributed to genetic drift. Data based on Wright's statistics indicate an excess of heterozygotes for most loci. Populations share the same alleles at most loci and are only slightly differentiated from each other (Fst = 0.06). Results suggest that gene flow between these isolated populations remains sufficiently high to override the effect of geographic isolation.

scholarly journals Genetic Divergence of Two Sitobion avenae Biotypes on Barley and Wheat in China

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 117
Author(s):  
Da Wang ◽  
Xiaoqin Shi ◽  
Deguang Liu ◽  
Yujing Yang ◽  
Zheming Shang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Host Plant ◽  
Genetic Divergence ◽  
Isolation By Distance ◽  
Critical Role ◽  
Geographic Distance ◽  
Sitobion Avenae ◽  
Insect Populations

Host plant affinity and geographic distance can play critical roles in the genetic divergence of insect herbivores and evolution of insect biotypes, but their relative importance in the divergence of insect populations is still poorly understood. We used microsatellite markers to test the effects of host plant species and geographic distance on divergence of two biotypes of the English grain aphid, Sitobion avenae (Fabricius). We found that clones of S. avenae from western provinces (i.e., Xinjiang, Gansu, Qinghai and Shaanxi) had significantly higher genetic diversity than those from eastern provinces (i.e., Anhui, Henan, Hubei, Zhejiang and Jiangsu), suggesting their differentiation between both areas. Based on genetic diversity and distance estimates, biotype 1 clones of eastern provinces showed high genetic divergence from those of western provinces in many cases. Western clones of S. avenae also showed higher genetic divergence among themselves than eastern clones. The Mantel test identified a significant isolation-by-distance (IBD) effect among different geographic populations of S. avenae, providing additional evidence for a critical role of geography in the genetic structure of both S. avenae biotypes. Genetic differentiation (i.e., FST) between the two biotypes was low in all provinces except Shaanxi. Surprisingly, in our analyses of molecular variance, non-significant genetic differentiation between both biotypes or between barley and wheat clones of S. avenae was identified, showing little contribution of host-plant associated differentiation to the divergence of both biotypes in this aphid. Thus, it is highly likely that the divergence of the two S. avenae biotypes involved more geographic isolation and selection of some form than host plant affinity. Our study can provide insights into understanding of genetic structure of insect populations and the divergence of insect biotypes.

scholarly journals Plant-associate interactions and diversification across trophic levels

2021 ◽  
Author(s):  
Jeremy B Yoder ◽  
Albert Dang ◽  
Caitlin MacGregor ◽  
Mikhail Plaza
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Species Interactions ◽  
Host Plants ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Trophic Levels ◽  
Population Structures ◽  
Genetic Structures ◽  
Antagonistic Interactions

Interactions between species are widely understood to have promoted the diversification of life on earth, but how interactions spur the the formation of new species remains unclear. Interacting species often become locally adapted to each other, but they may also be subject to shared dispersal limitations and environmental conditions. Moreover, theory predicts that different kinds of interactions have different effects on diversification. To better understand how species interactions promote diversification, we compiled published genetic data for host plants and intimately associated herbivores, parasites, and mutualists. We first tested whether host and associate population structures were correlated --- an indication of associates locally adapting to hosts --- and tested for confounding correlations with geographic distance or climate variation. We used Bayesian multiple regression to estimate the effect of host plant genetic differentiation on associate genetic differentiation over and above the confounding effects of geography and climate. We found that plant and associate genetic structures are indeed often congruent, but isolation by distance and by climate are also common. Multiple regressions established that the effect of host plants on associates is robust to accounting for geographic distance and climate. Finally, associate genetic structure was significantly explained by plant genetic structure more often in antagonistic interactions than in mutualistic ones. This supports a key prediction of coevolutionary theory, that antagonistic interactions promote diversity through local adaptation of antagonists to hosts, while mutualistic interactions promote diversity via the effect of hosts' geographic distribution on mutualists' dispersal.

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.

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