scholarly journals Environmental and genetic contributions to imperfect wMel-like Wolbachia transmission and frequency variation

2020 ◽  
Author(s):  
Michael T.J. Hague ◽  
Heidi Mavengere ◽  
Daniel R. Matute ◽  
Brandon S. Cooper
Keyword(s):  
Drosophila Melanogaster ◽  
Spatial Variation ◽  
Human Disease ◽  
Cytoplasmic Incompatibility ◽  
Frequency Variation ◽  
Maternal Transmission ◽  
Host Fitness ◽  
Fitness Effects ◽  
Genetic Contributions ◽  
Insight Into

ABSTRACTMaternally transmitted Wolbachia bacteria infect about half of all insect species. They usually show imperfect maternal transmission and often produce cytoplasmic incompatibility (CI). Irrespective of CI, Wolbachia frequencies tend to increase when rare only if they benefit host fitness. Several Wolbachia, including wMel that infects Drosophila melanogaster cause weak or no CI and persist at intermediate frequencies. On the island of São Tomé off West Africa, the frequencies of wMel-like Wolbachia infecting D. yakuba (wYak) and D. santomea (wSan) fluctuate, and the contributions of imperfect maternal transmission, fitness effects, and CI to these fluctuations are unknown. We demonstrate spatial variation in wYak frequency and transmission on São Tomé. Concurrent field estimates of imperfect maternal transmission do not predict spatial variation in wYak frequencies, which are highest at high altitudes where maternal transmission is the most imperfect. Genomic and genetic analyses provide little support for D. yakuba effects on wYak transmission. Instead, rearing at cool temperatures reduces wYak titer and increases imperfect transmission to levels observed on São Tomé. Using mathematical models of Wolbachia frequency dynamics and equilibria, we infer temporally variable imperfect transmission or spatially variable effects on host fitness and reproduction are required to explain wYak frequencies. In contrast, spatially stable wSan frequencies are plausibly explained by imperfect transmission, modest fitness effects, and weak CI. Our results provide insight into causes of wMel-like frequency variation in divergent hosts. Understanding this variation is crucial to explain Wolbachia spread and to improve wMel biocontrol of human disease in transinfected mosquito systems.

scholarly journals Environmental and Genetic Contributions to Imperfect wMel-Like Wolbachia Transmission and Frequency Variation

Genetics ◽  
2020 ◽  
Vol 215 (4) ◽  
pp. 1117-1132 ◽  
Author(s):  
Michael T. J. Hague ◽  
Heidi Mavengere ◽  
Daniel R. Matute ◽  
Brandon S. Cooper
Keyword(s):  
Drosophila Melanogaster ◽  
Spatial Variation ◽  
Cytoplasmic Incompatibility ◽  
Frequency Variation ◽  
Maternal Transmission ◽  
Host Fitness ◽  
Fitness Effects ◽  
Genetic Contributions ◽  
Drosophila Yakuba ◽  
Insight Into

Maternally transmitted Wolbachia bacteria infect about half of all insect species. They usually show imperfect maternal transmission and often produce cytoplasmic incompatibility (CI). Irrespective of CI, Wolbachia frequencies tend to increase when rare only if they benefit host fitness. Several Wolbachia, including wMel that infects Drosophila melanogaster, cause weak or no CI and persist at intermediate frequencies. On the island of São Tomé off West Africa, the frequencies of wMel-like Wolbachia infecting Drosophila yakuba (wYak) and Drosophila santomea (wSan) fluctuate, and the contributions of imperfect maternal transmission, fitness effects, and CI to these fluctuations are unknown. We demonstrate spatial variation in wYak frequency and transmission on São Tomé. Concurrent field estimates of imperfect maternal transmission do not predict spatial variation in wYak frequencies, which are highest at high altitudes where maternal transmission is the most imperfect. Genomic and genetic analyses provide little support for D. yakuba effects on wYak transmission. Instead, rearing at cool temperatures reduces wYak titer and increases imperfect transmission to levels observed on São Tomé. Using mathematical models of Wolbachia frequency dynamics and equilibria, we infer that temporally variable imperfect transmission or spatially variable effects on host fitness and reproduction are required to explain wYak frequencies. In contrast, spatially stable wSan frequencies are plausibly explained by imperfect transmission, modest fitness effects, and weak CI. Our results provide insight into causes of wMel-like frequency variation in divergent hosts. Understanding this variation is crucial to explain Wolbachia spread and to improve wMel biocontrol of human disease in transinfected mosquito systems.

scholarly journals A wMel Wolbachia variant in Aedes aegypti from field-collected Drosophila melanogaster with increased phenotypic stability under heat stress

2022 ◽  
Author(s):  
Xinyue Gu ◽  
Perran A Ross ◽  
Julio Rodriguez-Andres ◽  
Katie L. Robinson ◽  
Qiong Yang ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Stress ◽  
Aedes Aegypti ◽  
Cytoplasmic Incompatibility ◽  
Vector Competence ◽  
Temperature Tolerance ◽  
Seasonal Temperature ◽  
Maternal Transmission ◽  
Tropical Regions ◽  
Host Fitness

Mosquito-borne diseases such as dengue, Zika and chikungunya remain a major cause of morbidity and mortality across tropical regions. Population replacement strategies involving the wMel strain of Wolbachia are being used widely to control mosquito-borne diseases transmitted by Aedes aegypti. However, these strategies may be influenced by environmental temperature because wMel is vulnerable to heat stress. wMel infections in their native host Drosophila melanogaster are genetically diverse, but few transinfections of wMel variants have been generated in Ae. aegypti mosquitoes. Here we successfully transferred a wMel variant (termed wMelM) originating from a field-collected D. melanogaster population from Victoria, Australia into Ae. aegypti. The new wMelM variant (clade I) is genetically distinct from the original wMel transinfection (clade III) generated over ten years ago, and there are no genomic differences between wMelM in its original and transinfected host. We compared wMelM with wMel in its effects on host fitness, temperature tolerance, Wolbachia density, vector competence, cytoplasmic incompatibility and maternal transmission under heat stress in a controlled background. wMelM showed a higher heat tolerance than wMel, with stronger cytoplasmic incompatibility and maternal transmission when eggs were exposed to heat stress, likely due to higher overall densities within the mosquito. Both wMel variants had minimal host fitness costs, complete cytoplasmic incompatibility and maternal transmission, and dengue virus blocking under standard laboratory conditions. Our results highlight phenotypic differences between closely related Wolbachia variants. wMelM shows potential as an alternative strain to wMel in dengue control programs in areas with strong seasonal temperature fluctuations.

Taking Stock of Genetic Concepts in Fisheries Management

1991 ◽  
Vol 48 (4) ◽  
pp. 722-731 ◽  
Author(s):  
R. W. Gauldie
Keyword(s):  
Fisheries Management ◽  
Growth Rates ◽  
Allele Frequencies ◽  
Frequency Variation ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Meristic Count ◽  
Intuitive Idea ◽  
Selection Mechanisms ◽  
Insight Into

The historical development of the idea of isolated stocks of fish that can be managed as separate management units has been as strongly tied to the intuitive idea of separate races as it has been to the practical necessities of jurisprudence and the estimation of both biomass and sustainable yield by fisheries managers. Demonstrating the existence of isolated fish stocks and delineating their boundaries has generally proved unsuccessful. Various techniques ranging from meristic count differences to polymorphic allelism have usually failed. However, in the pursuit of isolated stocks, biochemists have uncovered a great deal of information about the variation of polymorphic allele frequencies over time and space. Following the shift in opinion away from stochastic to natural selection mechanisms in allele frequency variation, it is evident that the observed variation in allele frequencies allows more insight into the biology of fishes than into the breeding structure of populations. These insights argue against the idea of isolated stocks of fish with homogeneous growth rates that are the basis of the sustainable yield models in favour of migration-linked stocks with heterogeneous growth rates.

scholarly journals Comparative approaches to the study of physiology: Drosophila as a physiological tool

2013 ◽  
Vol 304 (3) ◽  
pp. R177-R188 ◽  
Author(s):  
Wendi S. Neckameyer ◽  
Kathryn J. Argue
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Pattern Formation ◽  
Signaling Pathways ◽  
Human Disease ◽  
Cognitive Disorders ◽  
Model System ◽  
Critical Questions ◽  
Developmental Signaling ◽  
Shed Light

Numerous studies have detailed the extensive conservation of developmental signaling pathways between the model system, Drosophila melanogaster, and mammalian models, but researchers have also profited from the unique and highly tractable genetic tools available in this system to address critical questions in physiology. In this review, we have described contributions that Drosophila researchers have made to mathematical dynamics of pattern formation, cardiac pathologies, the way in which pain circuits are integrated to elicit responses from sensation, as well as the ways in which gene expression can modulate diverse behaviors and shed light on human cognitive disorders. The broad and diverse array of contributions from Drosophila underscore its translational relevance to modeling human disease.

scholarly journals Zebrafish Models of Human Disease: Gaining Insight into Human Disease at ZFIN

ILAR Journal ◽  
2017 ◽  
Vol 58 (1) ◽  
pp. 4-16 ◽  
Author(s):  
Yvonne M. Bradford ◽  
Sabrina Toro ◽  
Sridhar Ramachandran ◽  
Leyla Ruzicka ◽  
Douglas G. Howe ◽  
...  
Keyword(s):  
Human Disease ◽  
Insight Into ◽  
Gaining Insight

scholarly journals Male age, host effects and the weak expression or non-expression of cytoplasmic incompatibility in Drosophila strains infected by maternally transmitted Wolbachia

2002 ◽  
Vol 80 (2) ◽  
pp. 79-87 ◽  
Author(s):  
K. TRACY REYNOLDS ◽  
ARY A. HOFFMANN
Keyword(s):  
Drosophila Melanogaster ◽  
Host Species ◽  
Cytoplasmic Incompatibility ◽  
Strain Differences ◽  
Large Impact ◽  
Young Males ◽  
Male Age ◽  
Weak Expression ◽  
Host Effects

In Drosophila melanogaster, the maternally inherited endocellular microbe Wolbachia causes cytoplasmic incompatibility (CI) in crosses between infected males and uninfected females. CI results in a reduction in the number of eggs that hatch. The level of CI expression in this species has been reported as varying from partial (a few eggs fail to hatch) to nonexistent (all eggs hatch). We show that male age in this host species has a large impact on the level of CI exhibited and explains much of this variability. Strong CI is apparent when young males are used in crosses. CI declines rapidly with male age, particularly when males are repeatedly mated. Wolbachia from a Canton S line that was previously reported as not causing CI does in fact induce CI when young males are used in crosses, albeit at a weaker level than in other D. melanogaster strains. The strain differences in CI expression are due to host background effects rather than differences in Wolbachia strains. These results highlight the importance of undertaking crosses with a range of male ages and nuclear backgrounds before ascribing particular host phenotypes to Wolbachia strains.

scholarly journals One prophage WO gene rescues cytoplasmic incompatibility in Drosophila melanogaster

2018 ◽  
Author(s):  
J. Dylan Shropshire ◽  
Jungmin On ◽  
Emily M. Layton ◽  
Helen Zhou ◽  
Seth R. Bordenstein
Keyword(s):  
Drosophila Melanogaster ◽  
Vector Control ◽  
Genetic Basis ◽  
Cytoplasmic Incompatibility ◽  
Embryo Rescue ◽  
Field Trials ◽  
Current Control ◽  
Drive System ◽  
World Health ◽  
Fitness Advantage

AbstractWolbachia are maternally-inherited, intracellular bacteria at the forefront of vector control efforts to curb arbovirus transmission. In international field trials, the cytoplasmic incompatibility (CI) drive system of wMel Wolbachia is deployed to replace target vector populations, whereby a Wolbachia– induced modification of the sperm genome kills embryos. However, Wolbachia in the embryo rescue the sperm genome impairment, and therefore CI results in a strong fitness advantage for infected females that transmit the bacteria to offspring. The two genes responsible for the wMel-induced sperm modification of CI, cifA and cifB, were recently identified in the eukaryotic association module of prophage WO, but the genetic basis of rescue is unresolved. Here we use transgenic and cytological approaches to demonstrate that cifA independently rescues CI and nullifies embryonic death caused by wMel Wolbachia in Drosophila melanogaster. Discovery of cifA as the rescue gene and previously one of two CI induction genes establishes a new ‘Two-by-One’ model that underpins the genetic basis of CI. Results highlight the central role of prophage WO in shaping Wolbachia phenotypes that are significant to arthropod evolution and vector control.Significance StatementThe World Health Organization recommended pilot deployment of Wolbachia-infected mosquitoes to curb viral transmission to humans. Releases of mosquitoes are underway worldwide because Wolbachia can block replication of these pathogenic viruses and deterministically spread by a drive system termed cytoplasmic incompatibility (CI). Despite extensive research, the underlying genetic basis of CI remains only half-solved. We recently reported that two prophage WO genes recapitulate the modification component of CI in a released strain for vector control. Here we show that one of these genes underpins rescue of CI. Together, our results reveal the complete genetic basis of this selfish trait and pave the way for future studies exploring WO prophage genes as adjuncts or alternatives to current control efforts.

scholarly journals PROPERTIES AND EVOLUTIONARY POTENTIAL OF NEWLY INDUCED TANDEM DUPLICATIONS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1982 ◽  
Vol 102 (1) ◽  
pp. 75-89
Author(s):  
Paul A Roberts ◽  
David J Broderick
Keyword(s):  
Drosophila Melanogaster ◽  
Linkage Disequilibrium ◽  
Tandem Duplication ◽  
Polytene Chromosomes ◽  
Primary Source ◽  
Evolutionary Potential ◽  
X Ray ◽  
Fitness Effects ◽  
New Genes ◽  
Tandem Duplications

ABSTRACT Most of some 33 X-ray-induced duplications recovered as Suppressors of Minute loci proved to be direct tandem duplications. When heterozygous, most duplications were crossover suppressors, and duplications of short to moderate size did not reduce the fitness of their bearers. Crossover suppression by tandem duplication may be attributed to intrastrand foldbacks of the type regularly seen in somatic polytene chromosomes. As a consequence, linkage disequilibrium between duplicated elements and normal chromosomes should be more profound than has been supposed. Tandem duplications appear to be predisposed by reason of frequency of generation, crossover suppression and fitness effects to serve as the primary source of new genes.

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