scholarly journals Genetic stability of Aedes aegypti populations following invasion by wMel Wolbachia

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Meng-Jia Lau ◽  
Thomas L. Schmidt ◽  
Qiong Yang ◽  
Jessica Chung ◽  
Lucien Sankey ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Geographic Location ◽  
Infection Status ◽  
Population Differences ◽  
Outlier Analysis ◽  
Genetic Changes ◽  
Genome Wide ◽  
And Behavior

Abstract Background Wolbachia wMel is the most commonly used strain in rear and release strategies for Aedes aegypti mosquitoes that aim to inhibit the transmission of arboviruses such as dengue, Zika, Chikungunya and yellow fever. However, the long-term establishment of wMel in natural Ae. aegypti populations raises concerns that interactions between Wolbachia wMel and Ae. aegypti may lead to changes in the host genome, which could affect useful attributes of Wolbachia that allow it to invade and suppress disease transmission. Results We applied an evolve-and-resequence approach to study genome-wide genetic changes in Ae. aegypti from the Cairns region, Australia, where Wolbachia wMel was first introduced more than 10 years ago. Mosquito samples were collected at three different time points in Gordonvale, Australia, covering the phase before (2010) and after (2013 and 2018) Wolbachia releases. An additional three locations where Wolbachia replacement happened at different times across the last decade were also sampled in 2018. We found that the genomes of mosquito populations mostly remained stable after Wolbachia release, with population differences tending to reflect the geographic location of the populations rather than Wolbachia infection status. However, outlier analysis suggests that Wolbachia may have had an influence on some genes related to immune response, development, recognition and behavior. Conclusions Ae. aegypti populations remained geographically distinct after Wolbachia wMel releases in North Australia despite their Wolbachia infection status. At some specific genomic loci, we found signs of selection associated with Wolbachia, suggesting potential evolutionary impacts can happen in the future and further monitoring is warranted.

scholarly journals Genetic Stability of Aedes aegypti Populations following Invasion by wMel Wolbachia

2021 ◽  
Author(s):  
Meng-Jia Lau ◽  
Tom Schmidt ◽  
Qiong Yang ◽  
Jessica Chung ◽  
Lucien Sankey ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Natural Populations ◽  
Geographic Location ◽  
Infection Status ◽  
Outlier Analysis ◽  
Genetic Changes ◽  
Genome Wide ◽  
And Behavior

Abstract BackgroundWolbachia wMel is the most used strain in mosquito rear and release strategies that aim to inhibit the transmission of arboviruses such as dengue, Zika, Chikungunya and yellow fever. However, the long-term establishment of wMel in natural populations of the dengue mosquito Aedes aegypti raises concerns that interactions between Wolbachia wMel and Ae. aegypti may lead to changes in the host genome, which could affect useful attributes of Wolbachia that allow it to invade and suppress disease transmission. ResultsWe applied an evolve-and-resequence approach to study genome-wide genetic changes in Ae. aegypti from the Cairns region, Australia, where Wolbachia wMel was first introduced more than 10 years ago. Mosquito samples were collected at three different time points in Gordonvale, Australia, covering the phase before (2010) and after (2013 and 2018) Wolbachia releases. An additional three locations where Wolbachia replacement happened at different times across the last decade were also sampled in 2018. We found that the genomes of mosquito populations mostly remained stable after Wolbachia release, with population differences tending to reflect the geographic location of the populations rather than Wolbachia infection status. However, outlier analysis suggests that Wolbachia may have had an influence on some genes related to immune response, development, recognition and behavior. ConclusionsAe. aegypti populations remained geographically distinct after Wolbachia wMel releases in North Australia despite their Wolbachia infection status. At some specific genomic loci, we found signs of selection associated with Wolbachia, suggesting potential evolutionary impacts can happen in the future and further monitoring is warranted.

scholarly journals Genetic stability of Aedes aegypti populations following invasion by wMel Wolbachia

2021 ◽  
Author(s):  
Meng-Jia Lau ◽  
Tom Schmidt ◽  
Qiong Yang ◽  
Jessica Chung ◽  
Ary A. Hoffmann
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Natural Populations ◽  
Geographic Location ◽  
Infection Status ◽  
Population Differences ◽  
Outlier Analysis ◽  
Genetic Changes ◽  
Genome Wide

Background: Wolbachia wMel play a major role in mosquito rear and release strategies that aim to inhibit the transmission of arboviruses such as dengue, Zika, Chikungunya and yellow fever. However, the long-term establishment of wMel in natural populations of the dengue mosquito Aedes aegypti raises concerns that interactions between Wolbachia wMel and Ae. aegypti may lead to changes in the host genome, which could affect useful attributes of Wolbachia that allow it to invade and suppress disease transmission. Results: We applied an evolve-and-resequence approach to study genome-wide genetic changes in Ae. aegypti from the Cairns region, Australia, where Wolbachia wMel was first introduced more than 10 years ago. Mosquito samples were collected at three different time points in Gordonvale, Australia, covering the phase before (2010) and after (2013 and 2018) Wolbachia releases; an additional three locations where Wolbachia replacement happened at different times across the last decade were also sampled in 2018. We found that in general, the genome of mosquito populations mostly remained stable after Wolbachia release, with any population differences tending to reflect the geographic location of the populations rather than Wolbachia infection status. Whereas on the other hand, outlier analysis suggested that Wolbachia may have had an influence on some genes related to immune response, development, recognition and behaviour. Conclusions: In general, Ae. aegypti populations remained geographically distinct after Wolbachia releases in North Australia despite their Wolbachia infection status. Whereas at some specific genomic loci, we found signs of selection associated with Wolbachia, suggesting potential evolutionary impacts can happen in the future and further monitoring is warranted.

scholarly journals A w AlbB Wolbachia transinfection displays stable phenotypic effects across divergent Aedes aegypti mosquito backgrounds

2021 ◽  
Author(s):  
Perran A. Ross ◽  
Xinyue Gu ◽  
Katie L. Robinson ◽  
Qiong Yang ◽  
Ellen Cottingham ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Cytoplasmic Incompatibility ◽  
Mosquito Control ◽  
Host Genotype ◽  
Egg Hatch ◽  
Genetic Changes ◽  
Control Programs ◽  
Nuclear Background ◽  
The Stability

Aedes mosquitoes harboring intracellular Wolbachia bacteria are being released in arbovirus and mosquito control programs. With releases taking place around the world, understanding the contribution of host variation to Wolbachia phenotype is crucial. We generated a Wolbachia transinfection ( w AlbB Q ) in Aedes aegypti and performed backcrossing to introduce the infection into Australian or Malaysian nuclear backgrounds. Whole Wolbachia genome sequencing shows that the w AlbB Q transinfection is near-identical to the reference w AlbB genome, suggesting few changes since the infection was first introduced to Ae. aegypti over 15 years ago. However, these sequences were distinct from other available w AlbB genome sequences, highlighting the potential diversity of w AlbB in natural Ae. albopictus populations. Phenotypic comparisons demonstrate effects of w AlbB infection on egg hatch and nuclear background on fecundity and body size, but no interactions between w AlbB infection and nuclear background for any trait. The w AlbB infection was stable at high temperatures and showed perfect maternal transmission and cytoplasmic incompatibility regardless of host background. Our results demonstrate the stability of w AlbB across host backgrounds and point to its long-term effectiveness for controlling arbovirus transmission and mosquito populations. Importance Wolbachia bacteria are being used to control the transmission of dengue and other arboviruses by mosquitoes. For Wolbachia release programs to be effective globally, Wolbachia infections must be stable across mosquito populations from different locations. In this study, we transferred Wolbachia (strain w AlbB) to Aedes aegypti mosquitoes with an Australian genotype and introduced the infection to Malaysian mosquitoes through backcrossing. We found that the phenotypic effects of Wolbachia are stable across both mosquito backgrounds. We sequenced the genome of w AlbB and found very few genetic changes despite spending over 15 years in a novel mosquito host. Our results suggest that the effects of Wolbachia infections are likely to remain stable across time and host genotype.

scholarly journals Genetic effects of long-term captive breeding on the endangered pygmy hog

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12212
Author(s):  
Deepanwita Purohit ◽  
Shivakumara Manu ◽  
Muthuvarmadam Subramanian Ram ◽  
Shradha Sharma ◽  
Harika Chinchilam Patnaik ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Captive Breeding ◽  
Mitochondrial Genomes ◽  
Captive Population ◽  
Genetic Changes ◽  
Captive Populations ◽  
Genome Wide ◽  
Pygmy Hog ◽  
Conservation Breeding

Long-term captive populations often accumulate genetic changes that are detrimental to their survival in the wild. Periodic genetic evaluation of captive populations is thus necessary to identify deleterious changes and minimize their impact through planned breeding. Pygmy hog (Porcula salvania) is an endangered species with a small population inhabiting the tall sub-Himalayan grasslands of Assam, India. A conservation breeding program of pygmy hog from six founders has produced a multi-generational captive population destined for reintroduction into the wild. However, the impact of conservation breeding on its genetic diversity remained undocumented. Here, we evaluate temporal genetic changes in 39 pygmy hogs from eight consecutive generations of a captive population using genome-wide SNPs, mitochondrial genomes, and MHC sequences, and explore the relationship between genetic diversity and reproductive success. We find that pygmy hog harbors a very low genome-wide heterozygosity (H) compared to other members of the Suidae family. However, within the captive population we find excess heterozygosity and a significant increase in H from the wild-caught founders to the individuals in subsequent generations due to the selective pairing strategy. The MHC and mitochondrial nucleotide diversities were lower in captive generations compared to the founders with a high prevalence of low-frequency MHC haplotypes and more unique mitochondrial genomes. Further, even though no signs of genetic inbreeding were observed from the estimates of individual inbreeding coefficient F and between individuals (FIS) in each generation, the kinship coefficient showed a slightly increasing trend in the recent generations, due to a relatively smaller non-random sample size compared to the entire captive population. Surprisingly, male pygmy hogs that had higher heterozygosity also showed lower breeding success. We briefly discuss the implications of our findings in the context of breeding management and recommend steps to minimize the genetic effects of long-term captive breeding.

scholarly journals Reduced competence to arboviruses following the sustainable invasion of Wolbachia into native Aedes aegypti from Southeastern Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
João Silveira Moledo Gesto ◽  
Gabriel Sylvestre Ribeiro ◽  
Marcele Neves Rocha ◽  
Fernando Braga Stehling Dias ◽  
Julia Peixoto ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Oral Feeding ◽  
Southeastern Brazil ◽  
Proof Of Concept ◽  
Small Community ◽  
High Infection ◽  
Promising Solution ◽  
Virus Blocking

AbstractField release of Wolbachia-infected Aedes aegypti has emerged as a promising solution to manage the transmission of dengue, Zika and chikungunya in endemic areas across the globe. Through an efficient self-dispersing mechanism, and the ability to induce virus-blocking properties, Wolbachia offers an unmatched potential to gradually modify wild Ae. aegypti populations turning them unsuitable disease vectors. Here we describe a proof-of-concept field trial carried out in a small community of Niterói, greater Rio de Janeiro, Brazil. Following the release of Wolbachia-infected eggs, we report here a successful invasion and long-term establishment of the bacterium across the territory, as denoted by stable high-infection indexes (> 80%). We have also demonstrated that refractoriness to dengue and Zika viruses, either thorough oral-feeding or intra-thoracic saliva challenging assays, was maintained over the adaptation to the natural environment of Southeastern Brazil. These findings further support Wolbachia’s ability to invade local Ae. aegypti populations and impair disease transmission, and will pave the way for future epidemiological and economic impact assessments.

scholarly journals Reduced competence to arboviruses following the sustainable invasion of Wolbachia into native Aedes aegypti from Niterói, Southeastern Brazil

2020 ◽  
Author(s):  
João Silveira Moledo Gesto ◽  
Gabriel Sylvestre Ribeiro ◽  
Marcele Neves Rocha ◽  
Fernando Braga Stehling Dias ◽  
Julia Peixoto ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Oral Feeding ◽  
Southeastern Brazil ◽  
Proof Of Concept ◽  
Small Community ◽  
High Infection ◽  
Promising Solution ◽  
Virus Blocking

AbstractField release of Wolbachia-infected Aedes aegypti has emerged as a promising solution to manage the transmission of dengue, Zika and chikungunya in endemic areas across the globe. Through an efficient self-dispersing mechanism, and the ability to induce virus-blocking properties, Wolbachia offers an unmatched potential to gradually modify wild Ae. aegypti populations turning them unsuitable disease vectors. Here in this work, a proof-of-concept field trial was carried out in a small community of Niterói, greater Rio de Janeiro. Following the release of Wolbachia-infected eggs, we reported a successful invasion and long-term establishment of the bacterium across the territory, as denoted by stable high-infection indexes (>80%). We have also demonstrated that refractoriness to dengue and Zika viruses, either thorough oral-feeding or intra-thoracic saliva challenging assays, were maintained over the adaptation to the natural environment of Southeastern Brazil. These findings further support Wolbachia’s ability to invade local Ae. aegypti populations and impair disease transmission, and shall pave the way for future epidemiological and economic impact assessments.

scholarly journals Odor-Specific Daily Rhythms in the Olfactory Sensitivity and Behavior of Aedes aegypti Mosquitoes

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 147 ◽  
Author(s):  
Diane Eilerts ◽  
Morgen VanderGiessen ◽  
Elizabeth Bose ◽  
Kyera Broxton ◽  
Clément Vinauger
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Molecular Mechanisms ◽  
Behavioral Plasticity ◽  
Fine Tuning ◽  
Olfactory Sensitivity ◽  
Olfactory Behavior ◽  
Host Interactions ◽  
Rhythmic Expression ◽  
And Behavior

Many biological processes and behaviors in mosquitoes display rhythmic patterns, allowing for fine tuning to cyclic environmental conditions. In mosquitoes, vector-host interactions are primarily mediated by olfactory signals. Previous studies have established that, in the malaria vector Anopheles gambiae, rhythmic expression of odorant binding proteins and takeout proteins in the antenna resulted in a corresponding rhythm in olfactory sensitivity to relevant host odors. However, it remained unclear how rhythms observed in olfactory sensitivity affect or explain rhythms in behavioral output, which ultimately impacts disease transmission. In order to address this knowledge gap, we quantified and compared patterns in locomotor activity, olfactory sensitivity, and olfactory behaviors in adult female Aedes aegypti mosquitoes. Here, we demonstrate an odorant-specific modulation of olfactory sensitivity in Ae. aegypti, decoupled from rhythms in olfactory behavior. Additionally, behavioral assays performed herein represent the first evidence of a time-dependence of the olfactory activation of behavior in Ae. aegypti mosquitoes. Results suggest that olfactory behavior of Aedes mosquitoes is modulated at both the peripheral (antenna) and central levels. As such, this work serves as a foundation for future studies aimed at further understanding the neural and molecular mechanisms underlying behavioral plasticity.

scholarly journals The queenslandensis and the type form of the dengue fever mosquito (Aedes aegypti L.) are genomically indistinguishable

2016 ◽  
Author(s):  
Gordana Rašić ◽  
Igor Filipović ◽  
Ashley G. Callahan ◽  
Darren Stanford ◽  
Abigail Chan ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Fever ◽  
Environmental Influence ◽  
Control Strategies ◽  
Nuclear Genome ◽  
Geographic Location ◽  
Color Variation ◽  
Rad Sequencing ◽  
Control Programs ◽  
Genome Wide

AbstractBackgroundThe mosquito Aedes aegypti (L.) is a major vector of viral diseases like dengue fever, Zika and chikungunya. Aedes aegypti exhibits high morphological and behavioral variation, some of which is thought to be of epidemiological significance. Globally distributed domestic Ae. aegypti have been traditionally grouped into (i) the very pale variety queenslandensis and (ii) the type form. Because the two color forms co-occur across most of their range, there is interest in understanding how freely they interbreed. This knowledge is particularly important for control strategies that rely on mating compatibilities between the release and target mosquitoes, such as Wolbachia releases and SIT. To answer this question, we analyzed nuclear and mitochondrial genome-wide variation in the co-occurring pale and type Ae. aegypti from northern Queensland (Australia) and Singapore.Methods/FindingsWe typed 74 individuals at a 1170 bp-long mitochondrial sequence and at 16,569 nuclear SNPs using a customized double-digest RAD sequencing. 11/29 genotyped individuals from Singapore and 11/45 from Queensland were identified as var. queenslandensis based on the diagnostic scaling patterns. We found 24 different mitochondrial haplotypes, seven of which were shared between the two forms. Multivariate genetic clustering based on nuclear SNPs corresponded to individuals’ geographic location, not their color. Several family groups consisted of both forms and three queenslandensis individuals were Wolbachia infected, indicating previous breeding with the type form which has been used to introduce Wolbachia into Ae. aegypti populations.ConclusionAedes aegypti queenslandensis are genomically indistinguishable from the type form, which points to these forms freely interbreeding at least in Australia and Singapore. Based on our findings, it is unlikely that the presence of very pale Ae. aegypti will affect the success of Aedes control programs based on Wolbachia-infected, sterile or RIDL mosquitoes.Author SummaryAedes aegypti, the most important vector of dengue and Zika, greatly varies in body color and behavior. Two domestic forms of this mosquito, the very pale queenslandensis and the browner type, are often found together in populations around the globe. Knowing how freely they interbreed is important for the control strategies such as releases of Wolbachia and sterile males. To answer this question, we used RAD sequencing to genotype samples of both forms collected in Singapore and northern Queensland. We did not find any association between the mitochondrial or nuclear genome-wide variation and color variation in these populations. Rather, “paleness” is likely to be a quantitative trait under some environmental influence. We also detected several queenslandensis individuals with the Wolbachia infection, indicating free interbreeding with the type form which has been used to introduce Wolbachia into Ae. aegypti populations. Overall, our data show that the very pale queenslandensis are not genomically separate, and their presence is unlikely to affect the success of Aedes control programs based on Wolbachia-infected, sterile or RIDL mosquitoes.

scholarly journals What can genomics tell us about the success of enhancement programs in anadromous Chinook salmon? A comparative analysis across four generations

2016 ◽  
Author(s):  
Charles D. Waters ◽  
Jeffrey J. Hard ◽  
Marine S.O. Brieuc ◽  
David E. Fast ◽  
Kenneth I. Warheit ◽  
...  
Keyword(s):  
Empirical Support ◽  
Source Population ◽  
Management Scenarios ◽  
Genetic Changes ◽  
Hatchery Fish ◽  
Genome Wide ◽  
Domestication Selection ◽  
Genetic Risks ◽  
Two Generations

Population enhancement through the release of cultured organisms can be an important tool for marine restoration. However, there has been considerable debate about whether releases effectively contribute to conservation and harvest objectives, and whether cultured organisms impact the fitness of wild populations. Pacific salmonid hatcheries on the West Coast of North America represent one of the largest enhancement programs in the world. Molecular-based pedigree studies on one or two generations have contributed to our understanding of the fitness of hatchery-reared individuals relative to wild individuals, and tend to show that hatchery fish have lower reproductive success. However, interpreting the significance of these results can be challenging because the long-term genetic and ecological effects of releases on supplemented populations are unknown. Further, pedigree studies have been opportunistic, rather than hypothesis driven, and have not provided information on “best case” management scenarios. Here, we present a comparative, experimental approach based on genome-wide surveys of changes in diversity in two hatchery lines founded from the same population. We demonstrate that gene flow with wild individuals can reduce divergence from the wild source population over four generations. We also report evidence for consistent genetic changes in a closed hatchery population that can be explained by both genetic drift and domestication selection. The results of this study suggest that genetic risks can be minimized over at least four generations with appropriate actions, and provide empirical support for a decision-making framework that is relevant to the management of hatchery populations.

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