scholarly journals High genetic diversity but no geographical structure of Aedes albopictus populations in Réunion Island

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Anne C. Latreille ◽  
Pascal Milesi ◽  
Hélène Magalon ◽  
Patrick Mavingui ◽  
Célestine M. Atyame
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Aedes Albopictus ◽  
Genetic Variance ◽  
Mosquito Control ◽  
Isolation By Distance ◽  
Virus Transmission ◽  
Reunion Island ◽  
High Genetic Diversity ◽  
Réunion Island

Abstract Background In recent years, the Asian tiger mosquito Aedes albopictus has emerged as a species of major medical concern following its global expansion and involvement in many arbovirus outbreaks. On Réunion Island, Ae. albopictus was responsible for a large chikungunya outbreak in 2005–2006 and more recently an epidemic of dengue which began at the end of 2017 and is still ongoing at the time of writing. This dengue epidemic has seen a high number of human cases in south and west coastal regions, while few cases have been reported in the north and east of the island. To better understand the role of mosquito populations in such spatial patterns of dengue virus transmission in Réunion Island, we examined the genetic diversity and population structure of Ae. albopictus sampled across the island. Results Between November 2016 and March 2017, a total of 564 mosquitoes were collected from 19 locations in three main climatic regions (West, East and Center) of Réunion Island and were genotyped using 16 microsatellite loci. A high genetic diversity was observed with 2–15 alleles per locus and the average number of alleles per population varying between 4.70–5.90. Almost all FIS values were significantly positive and correlated to individual relatedness within populations using a hierarchical clustering approach based on principal components analyses (HCPC). However, the largest part of genetic variance was among individuals within populations (97%) while only 3% of genetic variance was observed among populations within regions. Therefore, no distinguishable population structure or isolation by distance was evidenced, suggesting high rates of gene flow at the island scale. Conclusions Our results show high genetic diversity but no genetic structure of Ae. albopictus populations in Réunion Island thus reflecting frequent movements of mosquitoes between populations probably due to human activity. These data should help in the understanding of Ae. albopictus vector capacity and the design of effective mosquito control strategies.

scholarly journals Genetic Diversity and Population Structure of Chionanthus virginicus

2022 ◽  
Vol 147 (1) ◽  
pp. 62-69
Author(s):  
Phillip A. Wadl ◽  
Timothy A. Rinehart ◽  
Richard T. Olsen ◽  
Benjamin D. Waldo ◽  
Joseph H. Kirkbride
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Germplasm Collection ◽  
Eastern United States ◽  
High Genetic Diversity ◽  
Breeding Programs ◽  
Tree Form ◽  
Wide Range

The genus Chionanthus, known as fringetrees, is a member of the olive family (Oleaceae). Chionanthus virginicus is an understory tree or shrub with a wide range in forests of the eastern United States and is used as an ornamental tree that is known to be free of insects and disease in the wild. The species is tolerant of a wide range of environmental conditions, and there is interest in developing new cultivars with improved horticultural traits, such as tree form or upright growth habit and superior flowering display that are widely adapted. To identify genepools in the native range of C. virginicus for use in breeding programs, the genetic diversity and population structure were assessed for 274 individuals from 12 locations in four states (Florida, Maryland, North Carolina, and Texas) using 26 simple sequence repeats (SSRs). An average of 12.54 alleles/locus were detected, allelic richness averaged 2.80. Genetic differentiation was 0.11, indicating moderate differentiation among subpopulations. Despite the high genetic diversity and low population differentiation, Bayesian clustering analysis identified six genetic groups that match the geographic distribution of collection sites. Analysis of molecular variance indicated that most (82%) of the variation is explained within individuals, and 11% and 7% of the variation is due to differences among individuals within populations and among populations. Analysis of isolation by distance across all samples showed a weak positive relationship between geographic distance and genetic distance. The C. virginicus samples analyzed in this study indicate there is sufficient diversity for germplasm collection for use in breeding programs. Given the relatively moderate genetic differentiation, there are not likely to be unique islands of genetic diversity that may be missed when gathering parental materials for a breeding program

scholarly journals Strategic Approach, Advances, and Challenges in the Development and Application of the SIT for Area-Wide Control of Aedes albopictus Mosquitoes in Reunion Island

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 770
Author(s):  
Louis Clément Gouagna ◽  
David Damiens ◽  
Clélia F. Oliva ◽  
Sébastien Boyer ◽  
Gilbert Le Goff ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Disease Transmission ◽  
Mosquito Control ◽  
Control Strategies ◽  
Specific Treatment ◽  
Public Understanding ◽  
Reunion Island ◽  
Additional Tool ◽  
Awareness Campaigns ◽  
Réunion Island

The global expansion of Aedes albopictus, together with the absence of specific treatment and vaccines for most of the arboviruses it transmits, has stimulated the development of more sustainable and ecologically acceptable methods for control of disease transmission through the suppression of natural vector populations. The sterile insect technique (SIT) is rapidly evolving as an additional tool for mosquito control, offering an efficient and more environment-friendly alternative to the use of insecticides. Following the devastating chikungunya outbreak, which affected 38% of the population on Reunion Island (a French overseas territory in the southwest of the Indian Ocean), there has been strong interest and political will to develop effective alternatives to the existing vector control strategies. Over the past 10 years, the French Research and Development Institute (IRD) has established an SIT feasibility program against Ae. albopictus on Reunion Island in collaboration with national and international partners. This program aimed to determine whether the SIT based on the release of radiation-sterilized males is scientifically and technically feasible, and socially acceptable as part of a control strategy targeting the local Ae. albopictus population. This paper provides a review of a multi-year and a particularly broad scoping process of establishing the scientific and technological feasibility of the SIT against Ae. albopictus on Reunion Island. It also draws attention to some prerequisites of the decision-making process, through awareness campaigns to enhance public understanding and support, social adoption, and regulatory validation of the SIT pilot tests.

scholarly journals Population structure of Aedes albopictus from La Réunion Island (Indian Ocean) with respect to susceptibility to a dengue virus

Heredity ◽  
2001 ◽  
Vol 87 (3) ◽  
pp. 273-283 ◽  
Author(s):  
Christophe Paupy ◽  
Romain Girod ◽  
Maximin Salvan ◽  
François Rodhain ◽  
Anna-Bella Failloux
Keyword(s):  
Population Structure ◽  
Indian Ocean ◽  
Dengue Virus ◽  
Aedes Albopictus ◽  
Reunion Island ◽  
La Réunion ◽  
Réunion Island ◽  
La Réunion Island

scholarly journals Population genetics of Aedes albopictus (Diptera: Culicidae) in its native range in Lao People’s Democratic Republic

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Maysa Tiemi Motoki ◽  
Dina Madera Fonseca ◽  
Elliott Frederic Miot ◽  
Bruna Demari-Silva ◽  
Phoutmany Thammavong ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Aedes Albopictus ◽  
Isolation By Distance ◽  
Genetic Locus ◽  
Lao Pdr ◽  
Phylogenetic Network ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
The Usa

Abstract Background The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse) is an important worldwide invasive species and can be a locally important vector of chikungunya, dengue and, potentially, Zika. This species is native to Southeast Asia where populations thrive in both temperate and tropical climates. A better understanding of the population structure of Ae. albopictus in Lao PDR is very important in order to support the implementation of strategies for diseases prevention and vector control. In the present study, we investigated the genetic variability of Ae. albopictus across a north-south transect in Lao PDR. Methods We used variability in a 1337-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), to assess the population structure of Ae. albopictus in Lao PDR. For context, we also examined variability at the same genetic locus in samples of Ae. albopictus from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA. Results We observed very high levels of genetic polymorphism with 46 novel haplotypes in Ae. albopictus from 9 localities in Lao PDR and Thailand populations. Significant differences were observed between the Luangnamtha population and other locations in Lao PDR. However, we found no evidence of isolation by distance. There was overall little genetic structure indicating ongoing and frequent gene flow among populations or a recent population expansion. Indeed, the neutrality test supported population expansion in Laotian Ae. albopictus and mismatch distribution analyses showed a lack of low frequency alleles, a pattern often seen in bottlenecked populations. When samples from Lao PDR were analyzed together with samples from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA, phylogenetic network and Bayesian cluster analysis showed that most populations from tropical/subtropical regions are more genetically related to each other, than populations from temperate regions. Similarly, most populations from temperate regions are more genetically related to each other, than those from tropical/subtropical regions. Conclusions Aedes albopictus in Lao PDR are genetically related to populations from tropical/subtropical regions (i.e. Thailand, Singapore, and California and Texas in the USA). The extensive gene flow among locations in Lao PDR indicates that local control is undermined by repeated introductions from untreated sites.

scholarly journals Bat coronavirus phylogeography in the Western Indian Ocean

2019 ◽  
Author(s):  
Léa Joffrin ◽  
Steven M. Goodman ◽  
David A. Wilkinson ◽  
Beza Ramasindrazana ◽  
Erwan Lagadec ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Phylogenetic Analyses ◽  
Strong Association ◽  
Western Indian Ocean ◽  
Reunion Island ◽  
High Genetic Diversity ◽  
Soil Fertilization ◽  
Réunion Island ◽  
History Of ◽  
Bat Coronavirus

AbstractBats provide key ecosystem services such as crop pest regulation, pollination, seed dispersal, and soil fertilization. Bats are also major hosts for biological agents responsible for zoonoses, such as coronaviruses (CoVs). The islands of the Western Indian Ocean are identified as a major biodiversity hotspot, with more than 50 bat species. In this study, we tested 1,013 bats belonging to 36 species from Mozambique, Madagascar, Mauritius, Mayotte, Reunion Island and Seychelles, based on molecular screening and partial sequencing of the RNA-dependent RNA polymerase gene. In total, 88 bats (8.7%) tested positive for coronaviruses, with higher prevalence in Mozambican bats (20.5% ± 4.9%) as compared to those sampled on islands (4.5% ± 1.5%). Phylogenetic analyses revealed a large diversity of α- and β-CoVs and a strong signal of co-evolution between CoVs and their bat host species, with limited evidence for host-switching, except for bat species sharing day roost sites.ImportanceThis is the first study to report the presence of coronaviruses (CoVs) in bats in Mayotte, Mozambique and Reunion Island, and in insectivorous bats in Madagascar. Eight percent of the tested bats were positive for CoVs, with higher prevalence in continental Africa than on islands. A high genetic diversity of α- and β-CoVs was found, with strong association between bat host and virus phylogenies, supporting a long history of co-evolution between bats and their associated CoVs in the Western Indian Ocean. These results highlight that strong variation between islands does exist and is associated with the composition of the bat species community on each island. Future studies should investigate whether CoVs detected in these bats have a potential for spillover in other hosts.

scholarly journals Range reduction of the Oblong Rocksnail, Leptoxis compacta, shapes riverscape genetic patterns

2020 ◽  
Author(s):  
Aaliyah D. Wright ◽  
Nicole L. Garrison ◽  
Ashantye’ S. Williams ◽  
Paul D. Johnson ◽  
Nathan V. Whelan
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Human Impacts ◽  
Isolation By Distance ◽  
Extinction Risk ◽  
River System ◽  
High Genetic Diversity ◽  
Range Contraction ◽  
Genetic Patterns ◽  
Cahaba River

AbstractMany freshwater gastropod species face extinction, including 79% of species in the family Pleuroceridae. The Oblong Rocksnail, Leptoxis compacta, is a narrow range endemic pleurocerid from the Cahaba River basin in central Alabama that has seen rapid range contraction in the last 100 years. Such a decline is expected to negatively affect genetic diversity in the species. However, precise patterns of genetic variation and gene flow across the restricted range of L. compacta are unknown. This lack of information limits our understanding of human impacts on the Cahaba River system and Pleuroceridae. Here, we show that L. compacta has likely seen a species-wide decline in genetic diversity, but remaining populations have relatively high genetic diversity. We also report a contemporary range extension compared to the last published survey. Leptoxis compacta does not display an isolation by distance pattern, contrasting patterns seen in many riverine taxa. Our findings also indicate that historical range contraction has resulted in the absence of common genetic patterns seen in many riverine taxa like isolation by distance as the small distribution of L. compacta allows for relatively unrestricted gene flow across its remaining range despite limited dispersal abilities. Two collection sites had higher genetic diversity than others, and broodstock sites for future captive propagation and reintroduction efforts should utilize sites identified here as having the highest genetic diversity. Broadly, our results support the hypothesis that range contraction will result in the reduction of species-wide genetic diversity, and common riverscape genetic patterns cannot be assumed to be present in species facing extinction risk.

scholarly journals Range reduction of Oblong Rocksnail, Leptoxis compacta, shapes riverscape genetic patterns

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9789
Author(s):  
Aaliyah D. Wright ◽  
Nicole L. Garrison ◽  
Ashantye’ S. Williams ◽  
Paul D. Johnson ◽  
Nathan V. Whelan
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Human Impacts ◽  
Isolation By Distance ◽  
Extinction Risk ◽  
River System ◽  
High Genetic Diversity ◽  
Range Contraction ◽  
Genetic Patterns ◽  
Cahaba River

Many freshwater gastropod species face extinction, including 79% of species in the family Pleuroceridae. The Oblong Rocksnail, Leptoxis compacta, is a narrow range endemic pleurocerid from the Cahaba River basin in central Alabama that has seen rapid range contraction in the last 100 years. Such a decline is expected to negatively affect genetic diversity in the species. However, precise patterns of genetic variation and gene flow across the restricted range of L. compacta are unknown. This lack of information limits our understanding of human impacts on the Cahaba River system and Pleuroceridae. Here, we show that L. compacta has likely seen a species-wide decline in genetic diversity, but remaining populations have relatively high genetic diversity. We also report a contemporary range extension compared to the last published survey. Our findings indicate that historical range contraction has resulted in the absence of common genetic patterns seen in many riverine taxa like isolation by distance as the small distribution of L. compacta allows for relatively unrestricted gene flow across its remaining range despite limited dispersal abilities. Two collection sites had higher genetic diversity than others, and broodstock sites for future captive propagation and reintroduction efforts should utilize sites identified here as having the highest genetic diversity. Broadly, our results support the hypothesis that range contraction will result in the reduction of species-wide genetic diversity, and common riverscape genetic patterns cannot be assumed to be present in species facing extinction risk.

scholarly journals Genetic diversity and population structure of black cottonwood (Populus deltoides) revealed using simple sequence repeat markers

BMC Genetics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Cun Chen ◽  
Yanguang Chu ◽  
Changjun Ding ◽  
Xiaohua Su ◽  
Qinjun Huang
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Differentiation ◽  
River Basin ◽  
Simple Sequence Repeat ◽  
Populus Deltoides ◽  
Sequence Repeat ◽  
Black Cottonwood ◽  
High Genetic Diversity ◽  
Simple Sequence

Abstract Background Black cottonwood (Populus deltoides) is one of the keystone forest tree species, and has become the main breeding parents in poplar hybrid breeding. However, the genetic diversity and population structure of the introduced resources are not fully understood. Results In the present study, five loci containing null alleles were excluded and 15 pairs of SSR (simple sequence repeat) primers were used to analyze the genetic diversity and population structure of 384 individuals from six provenances (Missouri, Iowa, Washington, Louisiana, and Tennessee (USA), and Quebec in Canada) of P. deltoides. Ultimately, 108 alleles (Na) were detected; the expected heterozygosity (He) per locus ranged from 0.070 to 0.905, and the average polymorphic information content (PIC) was 0.535. The provenance ‘Was’ had a relatively low genetic diversity, while ‘Que’, ‘Lou’, and ‘Ten’ provenances had high genetic diversity, with Shannon’s information index (I) above 1.0. The mean coefficient of genetic differentiation (Fst) and gene flow (Nm) were 0.129 and 1.931, respectively. Analysis of molecular variance (AMOVA) showed that 84.88% of the genetic variation originated from individuals. Based on principal coordinate analysis (PCoA) and STRUCTURE cluster analysis, individuals distributed in the Mississippi River Basin were roughly classified as one group, while those distributed in the St. Lawrence River Basin and Columbia River Basin were classified as another group. The cluster analysis based on the population level showed that provenance ‘Iow’ had a small gene flow and high degree of genetic differentiation compared with the other provenances, and was classified into one group. There was a significant relationship between genetic distance and geographical distance. Conclusions P. deltoides resources have high genetic diversity and there is a moderate level of genetic differentiation among provenances. Geographical isolation and natural conditions may be the main factors causing genetic differences among individuals. Individuals reflecting population genetic information can be selected to build a core germplasm bank. Meanwhile, the results could provide theoretical support for the scientific management and efficient utilization of P. deltoides genetic resources, and promote the development of molecular marker-assisted breeding of poplar.

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