scholarly journals Temperature-Inducible Precision Guided Sterile Insect Technique

2021 ◽  
Author(s):  
Nikolay P Kandul ◽  
Junru Liu ◽  
Omar Akbari
Keyword(s):  
Drosophila Melanogaster ◽  
Gold Standard ◽  
Sterile Insect Technique ◽  
Population Control ◽  
Insect Population ◽  
Proof Of Concept ◽  
Control Programs ◽  
True Breeding ◽  
Genetic Cross ◽  
Automate Production

Releases of sterile males are the gold standard for many insect population control programs, and precise sex sorting to remove females prior to male releases is essential to the success of these operations. To advance traditional methods for scaling the generation of sterile males, we previously described a CRISPR-mediated precision-guided sterile insect technique (pgSIT), in which Cas9 and gRNA strains are genetically crossed to generate sterile males for release. While effective at generating F1  sterile males, pgSIT requires a genetic cross between the two parental strains which requires maintenance and sexing of two strains in a factory. Therefore, to further advance pgSIT by removing this crossing step, here we describe a next-generation Temperature-Inducible pgSIT (TI-pgSIT) technology and demonstrate its proof-of-concept in Drosophila melanogaster. Importantly, we were able to develop a true-breeding strain for TI-pgSIT that eliminates the requirement for sex sorting, a feature that may help further automate production at scale.

scholarly journals Genetically engineered insects with sex-selection and genetic incompatibility enable population suppression

2021 ◽  
Author(s):  
Ambuj Upadhyay ◽  
Nathan Feltman ◽  
Adam Sychla ◽  
Siba Das ◽  
Maciej Maselko ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Reproduction ◽  
Pest Control ◽  
Sterile Insect Technique ◽  
Genetically Engineered ◽  
Sex Selection ◽  
Proof Of Concept ◽  
Wild Type ◽  
Genetic Incompatibility ◽  
Population Suppression

Engineered Genetic Incompatibility (EGI) is a method to create species-like barriers to sexual reproduction. It has applications in pest control that mimic Sterile Insect Technique when only EGI males are released. This can be facilitated by introducing conditional female-lethality to EGI strains to generate a sex-sorting incompatible male system (SSIMS). Here we demonstrate a proof of concept by combining tetracycline-controlled female lethality constructs with a pyramus-targeting EGI line in the model insect Drosophila melanogaster. We show that both functions (incompatibility and sex-sorting) are robustly maintained in the SSIMS line and that this approach is effective for population suppression in cage experiments. Further we show that SSIMS males remain competitive with wild-type males for reproduction with wild-type females, including at the level of sperm competition.

The Twenty-Five-Year FDA Approval Controversy

2017 ◽  
Author(s):  
William Green
Keyword(s):  
Population Control ◽  
Obstetrics And Gynecology ◽  
Marketing Approval ◽  
Approval Process ◽  
Control Programs ◽  
Drug Risk ◽  
Fda Approval ◽  
Political Controversy ◽  
Long Acting ◽  
Risk Acceptability

Judith Weisz's story of the politics of drug risk management shifts its focus to Depo-Provera's lengthy FDA marketing approval process. Here her story explores the scientific and political controversy over the FDA's assessment of the drug's risk and its policy judgments about the risk acceptability of its marketing approval. The controversy was dominated by the fear that the drug could cause breast, endometrial, and cervical cancer, and by Depo-Provera's uniqueness as a long-acting contraceptive and its use in international population control programs. The controversy began when the FDA relied on its Obstetrics and Gynecology Advisory Committee to grant the drug limited marketing approval in 1974, which it withdrew after congressional criticism, and then, following an intra-agency review, disapproved the drug for general contraceptive marketing which, once again, brought congressional scrutiny because of its impact on international family planning programs. An FDA Public Board of Inquiry, convened at Upjohn's request and chaired by Judith Weisz, conducted an intensive scientific assessment of the drug's animal and human studies at its 1983 hearings and then made a recommendation, accepted by the FDA in 1986, to disapprove the drug for general contraceptive marketing.

Sex ratio manipulation for insect population control.

2014 ◽  
pp. 83-100 ◽  
Author(s):  
P. A. Papathanos ◽  
N. Windbichler ◽  
O. S. Akbari
Keyword(s):  
Sex Ratio ◽  
Population Control ◽  
Insect Population

scholarly journals Transforming insect population control with precision guided sterile males with demonstration in flies

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Nikolay P. Kandul ◽  
Junru Liu ◽  
Hector M. Sanchez C. ◽  
Sean L. Wu ◽  
John M. Marshall ◽  
...  
Keyword(s):  
Population Control ◽  
Insect Population

scholarly journals A Gold Standard, CRISPR/Cas9-Based Complementation Strategy Reliant on 24 Nucleotide Bookmark Sequences

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 458 ◽  
Author(s):  
François M. Seys ◽  
Peter Rowe ◽  
Edward L. Bolt ◽  
Christopher M. Humphreys ◽  
Nigel P. Minton
Keyword(s):  
Gold Standard ◽  
Mutant Allele ◽  
Target Sequence ◽  
Proof Of Concept ◽  
Wild Type ◽  
Guide Rna ◽  
Simple Strategy ◽  
Clostridium Autoethanogenum ◽  
Gene Knockouts

Phenotypic complementation of gene knockouts is an essential step in establishing function. Here, we describe a simple strategy for ‘gold standard’ complementation in which the mutant allele is replaced in situ with a wild type (WT) allele in a procedure that exploits CRISPR/Cas9. The method relies on the prior incorporation of a unique 24 nucleotide (nt) ‘bookmark’ sequence into the mutant allele to act as a guide RNA target during its Cas9-mediated replacement with the WT allele. The bookmark comprises a 23 nt Cas9 target sequence plus an additional nt to ensure the deletion is in-frame. Here, bookmarks are tailored to Streptococcus pyogenes CRISPR/Cas9 but could be designed for any CRISPR/Cas system. For proof of concept, nine bookmarks were tested in Clostridium autoethanogenum. Complementation efficiencies reached 91%. As complemented strains are indistinguishable from their progenitors, concerns over contamination may be satisfied by the incorporation of ‘watermark’ sequences into the complementing genes.

scholarly journals Demography of feral camels in central Australia and its relevance to population control

2010 ◽  
Vol 32 (1) ◽  
pp. 11 ◽  
Author(s):  
A. R. Pople ◽  
S. R. McLeod
Keyword(s):  
Population Control ◽  
Northern Territory ◽  
Adult Survival ◽  
Large Mammals ◽  
Limited Data ◽  
Control Programs ◽  
Rate Of Increase ◽  
Zero Growth ◽  
Central Australia ◽  
Alternative Species

Since their release over 100 years ago, camels have spread across central Australia and increased in number. Increasingly, they are being seen as a pest, with observed impacts from overgrazing and damage to infrastructure such as fences. Irregular aerial surveys since 1983 and an interview-based survey in 1966 suggest that camels have been increasing at close to their maximum rate. A comparison of three models of population growth fitted to these, albeit limited, data suggests that the Northern Territory population has indeed been growing at an annual exponential rate of r = 0.074, or 8% per year, with little evidence of a density-dependent brake. A stage-structured model using life history data from a central Australian camel population suggests that this rate approximates the theoretical maximum. Elasticity analysis indicates that adult survival is by far the biggest influence on rate of increase and that a 9% reduction in survival from 96% is needed to stop the population growing. In contrast, at least 70% of mature females need to be sterilised to have a similar effect. In a benign environment, a population of large mammals such as camels is expected to grow exponentially until close to carrying capacity. This will frustrate control programs, because an ever-increasing number of animals will need to be removed for zero growth the longer that culling or harvesting effort is delayed. A population projection for 2008 suggests ~10 500 animals need to be harvested across the Northern Territory. Current harvests are well short of this. The ability of commercial harvesting to control camel populations in central Australia will depend on the value of animals, access to animals and the presence of alternative species to harvest when camels are at low density.

scholarly journals Insect Population Control by Homing Endonuclease-Based Gene Drive: An Evaluation inDrosophila melanogaster

Genetics ◽  
2011 ◽  
Vol 188 (1) ◽  
pp. 33-44 ◽  
Author(s):  
Yuk-Sang Chan ◽  
Daniel A. Naujoks ◽  
David S. Huen ◽  
Steven Russell
Keyword(s):  
Population Control ◽  
Homing Endonuclease ◽  
Insect Population ◽  
Gene Drive
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