scholarly journals Genetic analysis of medfly populations in an area of sterile insect technique applications

2021 ◽  
Author(s):  
Rubén Sancho ◽  
Ana Guillem-Amat ◽  
Elena López-Errasquín ◽  
Lucas Sánchez ◽  
Félix Ortego ◽  
...  
Keyword(s):  
Genetic Markers ◽  
Sterile Insect Technique ◽  
Ceratitis Capitata ◽  
Natural Populations ◽  
Low Frequency ◽  
Fruit Fly ◽  
Wild Populations ◽  
Genetic Sexing ◽  
Environmental Implications ◽  
Genetic Sexing Strains

AbstractThe sterile insect technique (SIT) is widely used in integrated pest management programs for the control of the Mediterranean fruit fly (medfly), Ceratitis capitata. The genetic interactions between the released individuals from the genetic sexing strains (GSS), used for SIT applications worldwide, and wild individuals have not been studied. Under the hypothesis that a number of Vienna GSS individuals released to the field might not be completely sterile and may produce viable offspring, we have analyzed medfly Spanish field populations to evaluate the presence of Vienna strain genetic markers. To this goal, we have used contrasted nuclear and mitochondrial genetic markers, and two novel sets of nuclear polymorphisms with the potential to be markers to discriminate between Vienna and wild individuals. Nuclear Vienna markers located on the 5th chromosome of Vienna males have been found in 2.2% (19 from 875) of the Spanish wild medfly females captured at the area where SIT is applied. In addition, a female-inherited mitochondrial Vienna marker has been found in two from the 19 females showing nuclear Vienna markers. The detection of several of these markers in single individuals represents evidence of the introgression of Vienna strain into natural populations. However, alternative explanations as their presence at low frequency in wild populations in the studied areas cannot be fully discarded. The undesired release of non-fully sterile irradiated GSS individuals into the field and their interactions with wild flies, and the potential environmental implications should be taken into account in the application of the SIT.

scholarly journals Comparison of classical and transgenic genetic sexing strains of Mediterranean fruit fly (Diptera: Tephritidae) for application of the sterile insect technique

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208880 ◽  
Author(s):  
José S. Meza ◽  
Ihsan ul Haq ◽  
Marc J. B. Vreysen ◽  
Kostas Bourtzis ◽  
Georgios A. Kyritsis ◽  
...  
Keyword(s):  
Sterile Insect Technique ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Genetic Sexing ◽  
Genetic Sexing Strains

scholarly journals Genetic structure and symbiotic profile of worldwide natural populations of the Mediterranean fruit fly, Ceratitis capitata

BMC Genetics ◽  
2020 ◽  
Vol 21 (S2) ◽  
Author(s):  
Katerina Nikolouli ◽  
Antonios A. Augustinos ◽  
Panagiota Stathopoulou ◽  
Elias Asimakis ◽  
Anastasios Mintzas ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Bacterial Communities ◽  
Ceratitis Capitata ◽  
Natural Populations ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Wild Populations ◽  
Mating Competitiveness ◽  
Biological Quality ◽  
The Mediterranean

Abstract Background The Mediterranean fruit fly, Ceratitis capitata, is a cosmopolitan agricultural pest of worldwide economic importance and a model for the development of the Sterile Insect Technique (SIT) for fruit flies of the Tephritidae family (Diptera). SIT relies on the effective mating of laboratory-reared strains and natural populations, and therefore requires an efficient mass-rearing system that will allow for the production of high-quality males. Adaptation of wild flies to an artificial laboratory environment can be accompanied by negative effects on several life history traits through changes in their genetic diversity and symbiotic communities. Such changes may lead to reduced biological quality and mating competitiveness in respect to the wild populations. Profiling wild populations can help understand, and maybe reverse, deleterious effects accompanying laboratory domestication thus providing insects that can efficiently and effectively support SIT application. Results In the present study, we analyzed both the genetic structure and gut symbiotic communities of natural medfly populations of worldwide distribution, including Europe, Africa, Australia, and the Americas. The genetic structure of 408 individuals from 15 distinct populations was analyzed with a set of commonly used microsatellite markers. The symbiotic communities of a subset of 265 individuals from 11 populations were analyzed using the 16S rRNA gene-based amplicon sequencing of single individuals (adults). Genetic differentiation was detected among geographically distant populations while adults originated from neighboring areas were genetically closer. Alpha and beta diversity of bacterial communities pointed to an overall reduced symbiotic diversity and the influence of the geographic location on the bacterial profile. Conclusions Our analysis revealed differences both in the genetic profile and the structure of gut symbiotic communities of medfly natural populations. The genetic analysis expanded our knowledge to populations not analyzed before and our results were in accordance with the existing scenarios regarding this species expansion and colonization pathways. At the same time, the bacterial communities from different natural medfly populations have been characterized, thus broadening our knowledge on the microbiota of the species across its range. Genetic and symbiotic differences between natural and laboratory populations must be considered when designing AW-IPM approaches with a SIT component, since they may impact mating compatibility and mating competitiveness of the laboratory-reared males. In parallel, enrichment from wild populations and/or symbiotic supplementation could increase rearing productivity, biological quality, and mating competitiveness of SIT-important laboratory strains.

scholarly journals Lessons from Drosophila: Engineering Genetic Sexing Strains with Temperature-Sensitive Lethality for Sterile Insect Technique Applications

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 243
Author(s):  
Thu N. M. Nguyen ◽  
Amanda Choo ◽  
Simon W. Baxter
Keyword(s):  
Rna Polymerase Ii ◽  
Sterile Insect Technique ◽  
Genetic Research ◽  
Point Mutations ◽  
Random Mutagenesis ◽  
Fruit Fly ◽  
Temperature Sensitive ◽  
Agricultural Pests ◽  
Genetic Sexing ◽  
Genetic Sexing Strains

A major obstacle of sterile insect technique (SIT) programs is the availability of robust sex-separation systems for conditional removal of females. Sterilized male-only releases improve SIT efficiency and cost-effectiveness for agricultural pests, whereas it is critical to remove female disease-vector pests prior to release as they maintain the capacity to transmit disease. Some of the most successful Genetic Sexing Strains (GSS) reared and released for SIT control were developed for Mediterranean fruit fly (Medfly), Ceratitis capitata, and carry a temperature sensitive lethal (tsl) mutation that eliminates female but not male embryos when heat treated. The Medfly tsl mutation was generated by random mutagenesis and the genetic mechanism causing this valuable heat sensitive phenotype remains unknown. Conditional temperature sensitive lethal mutations have also been developed using random mutagenesis in the insect model, Drosophila melanogaster, and were used for some of the founding genetic research published in the fields of neuro- and developmental biology. Here we review mutations in select D. melanogaster genes shibire, Notch, RNA polymerase II 215kDa, pale, transformer-2, Dsor1 and CK2α that cause temperature sensitive phenotypes. Precise introduction of orthologous point mutations in pest insect species with CRISPR/Cas9 genome editing technology holds potential to establish GSSs with embryonic lethality to improve and advance SIT pest control.

Improved stability of genetic sex-separation strains for the Mediterranean fruit fly, Ceratitis capitata

Genome ◽  
1994 ◽  
Vol 37 (1) ◽  
pp. 72-82 ◽  
Author(s):  
G. Franz ◽  
E. Gencheva ◽  
Ph. Kerremans
Keyword(s):  
Ceratitis Capitata ◽  
Recombination Frequency ◽  
Fruit Fly ◽  
Mass Rearing ◽  
Temperature Sensitive ◽  
Genetic Sexing ◽  
Male Recombination ◽  
Comparable Level ◽  
Improved Stability ◽  
Genetic Sexing Strains

In the existing genetic sexing strains for the medfly, Ceratitis capitata, male recombination leads to breakdown of the sexing mechanism under mass rearing conditions. The rate of breakdown depends on the recombination frequency and on the fitness of the recombinants. We have tested two different sexing genes, white pupa and a temperature sensitive lethal, in combination with the translocation T(Y;5)30C. Both sexing strains broke down, although at very different rates. In the case of the white pupa strain, 3.5% recombinants were observed after rearing the strain for 15 generations. The second strain, utilizing white pupa and the temperature sensitive lethal as selectable markers, already reached a comparable level after six generations and was broken down completely in the ninth generation. In these strains the frequency of recombination is high because the breakpoint of T(Y;5)30C and the sexing gene(s) are far apart. To remedy the situation, we have isolated four new translocations with breakpoints located closer to the sexing genes. Mass rearing was simulated for several generations with strains based on these translocations and no breakdown was observed under the conditions used.Key words: medfly, sterile insect technique, genetic sexing, recombination.

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