Cas9

Terms associated with the butterfly wings. For detailed explanation, refer Glossary of entomology terms.

Somatic Mutagenesis as a Powerful Functional Genomics Tool in Insects

Two recent papers published in the Proceedings of the National Academy of Sciences are notable examples of using the CRISPR/Cas9 system to create somatic mutants to probe gene function.  Mazo-Varga et. al (2017) and Zhang et al. (2017). Both studies explore […]

Gene Drive

Will CRISPR/Cas9 Gene Drives Spread and How Could They Be Prevented From Doing So?

In an interesting paper published in PNAS, Tanaka, Stone and Nelson (2017) explore the potential for spatial spread of CRISPR/Cas9 gene drives. The authors examine a continuous time, spatial generalisation of the CRISPR/Cas9 population genetics model published by Unckless et […]

A recent scheme showing the consequences of distorting mosquito sex ratios using a "precision" drive system.

Strategies for Driving Out Invasive Species

Prowse et al. (2017) present their modelling work in the Proceedings of The Royal Society B on various different CRISPR/Cas9-based gene drives aimed at suppressing populations of exotic vertebrate species on islands (focusing on mice (Mus musculus)).  The issues addressed […]

High Knock in/out Rates in Aedes aegypti Expressing Cas9 from a Transgene.

  Li et al have published some interesting data on the preprint server bioRΧiv regarding the creation and use of Aedes aegypti lines expressing an SpCas9 transgene in the germline.  The report substantial improvements in gRNA-mediated mutagenesis rates. Cas9 mediated […]

Drosophila melanogaster

Cas9 Expression Patterns Impact on Resistance Evolution in Different Genetic Backgrounds

Gene drive systems are sensitive to the evolution of resistance in the form of polymorphisms in the guide RNA’s target DNA sequence.  Champer et al. (2017) have recently reported on their exploration of how Cas9 expression patterns as well as […]

Trojan Female Technique: Mitochondria-based population suppression.

The ‘Trojan Female Technique” is a genetics-based population suppression strategy.  Wolff et al.(2017) report results of empirical tests of the idea using Drosophila melanogaster as a model system and show net population suppression. Genetics-based pest control strategies are becoming increasingly […]

Cas9 with functional domains highlighted in relation to target DNA and guideRNA

RAD51 and Valporic Acid Enhance Cas9-induced HR

Takayama et al (2017) describe in Nucleic Acids Research how they increased the frequency of biallelic editing of genes in human ES/iPS cells and their findings may be useful to insect biologists. The efficiency of Cas9-mediated homologous recombination (HR) can […]

Cas9 Mutagenesis in Houseflies Confirms Male Determining Factor Identification

Sharma et al. (2107) report in a recent issue of Science the identification of a male determining factor in the housefly Musca domestica and provide convincing reverse genetic confirmatory evidence using dsRNA-mediated gene silencing and Cas9-mediated mutagenesis. Alternative splicing of […]

Medfly By Alvesgaspar - https://commons.wikimedia.org/w/index.php?curid=5027949

DNA-free genome editing in the agricultural pest Ceratitis capitata

The genome editing revolution creates new opportunities to improve pest management strategies, yet biosafety concerns over off-target effects and the use of foreign DNA present roadblocks to the development of modified organisms destined for field use. In a recent addition […]

Aedes aegypti, vector of Dengue virus

Cre/lox-Recombinase-Mediated Cassette Exchange in Aedes aegypti

Häcker et al 2017 reports the use of Cre/lox Recombination-Mediated Cassette Exchange (RMCE) in Aedes aegypti providing a pathway for interrogating specific genomic locations for the use of transgenic constructs in future genetic control methods. Häcker et al 2017 first generated […]

Call for Sweeping Moratorium on Gene Drive Research and Application at UN Biodiversity Conference

The UN Convention on Biological Diversity is currently holding their Biodiversity Conference in Cancun, Mexico.  Monday 160 organizations from six continents released a statement calling for a global moratorium on all work on gene drives, including laboratory research.   The […]

Male Locusta migratoria migratorioides photographed in Katavi National Park, Tanzania

Orco Knockout Mutants of Locusta migratoria

‎  A recent report by Li et al. demonstrates that by using a state-of-the-art CRISPR/Cas9 genome editing, it is now possible to study the function of Orco in the locust, Locusta migratoria .  The gene odorant receptor co-receptor (Orco) encodes […]

Guide RNA interacting with target DNA. Image credit: William Reid

Guide-RNA Engineering – Enhancing Activity and Function

The functionality of Cas9 is determined in part by the guide RNA with which it is associated. Norwak et al.(2016) review briefly how guide RNAs can be modified to enhance their function and to functionalize them in novel ways. Norwak […]

CRISPR-SD, a programmable Cas9 approach to generating X-shredder lines in insects with XY mating systems

In a recent paper in Scientific Reports, Galizi, Hammond, et al report on the use of CRISPR-Cas9 to develop a sex-distortion system in Anopheles gambiae, which they termed CRISPRSD. Earlier, the group had demonstrated that transgenic An. gambaie expressing the […]

OLYMPUS DIGITAL CAMERA

Gene Editing Spodoptera

Three papers recently described successful CRISPR/Cas9 mutagenesis in two species of Spodoptera.  Spodoptera litura and S. littoralis. Bi et al (2016) use Cas9 to create somatic mutations in S. litura in developmental gene abdominal-A, abd-A, and analyzed the resulting larvae […]

A selfish gene (blue) spreading through a mosquito population

U.S. National Academy of Science’s Report on Gene Drive Research

The United States National Academy of Sciences published a report entitled Gene Drives on the Horizon: Advancing Science, Navigating Uncertainty, and Aligning Research with Public Values recently.  The report was written by the Committee on Gene Drive Research in Non-Human […]

Phosphorothioate oligomers increase knock-in frequency and precision in TALEN- and Cas9-mediated genome editing

In a recent paper by Renaud et al. (2016), the authors investigate methods to increase genome editing knock-in efficiency by modifying the chemistry of the donor oligomers to be resistant to nuclease activity. The modifications they tested included locked nucleic […]

A selfish gene (blue) spreading through a mosquito population

Insect Gene Drives – Reviewed and Compared

Champer et al have published a review on the topic of engineered gene drives to manipulate wild populations in a recent Nature Reviews Genetics. Recent attention on Cas9-based gene drive systems has raised the awareness of these types of genetic […]

Danaus plexippus By William Warby (https://flic.kr/p/dtKZF2) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Monarch Reverse Genetics

Markert et al. just reported their effective use Cas9 and TALENs to knock out cryptochrome 2 and clock in Danaus plexippus using some strategies and approaches that are generally useful to insect scientists and much more efficient than earlier reports […]

Animal and Insect Transgenics – Parallels

James Murray and Elizabeth Maga recently recounted briefly the development and evolution of animal transgenic technologies in a recent issue of Transgenic Research and the similarities and differences between the development and evolution of insect transgenic technologies, which were ongoing […]

Adult male spotted wing drosophila, Drosophilia suzukii (Matsumura). Photograph by Martin Hauser, California Department of Food and Agriculture.

Gene Editing in an Invasive Species

Li and Scott report their successful use of Cas9 to knockout two genes in Drosophila suzukii in a recent issue of Biochemical and Biophysical Research Communications. Drosophila suzukii or the spotted wing Drosophila although a native of Asia has recently […]

Enhancing Homology Repair-Mediated Genome Editing

In a recent paper in Nature Biotechnology, Richardson et al (2016) report on the interaction of target-site bound Cas9 and dCas9 on DNA strand accessibility- and have identified an optimized approach to increase homologous recombination (HR) mediated repair. They found […]

Synthetic gene drive system based on site specific DNA endonucleases (homing endonucleases, ZFN, TALENS, Cas9). Target sites and homology arms are chosen so that the endonuclease and associated genes (gRNA and other transgenes) are copied into homologous chromosomes.

An Overview of Gene Drive

Gantz and Bier reflect on and consider the implications of Cas9-based genome editing on genetics in a recent Bioessays that is worth reading if you are trying to keep up on this rapidly evolving part of the genetics ecosystem. Not […]

Parhyale hawaiensis

Somatic Editing in Parhyale hawaiensis for Loss-of-Function Analysis

In a recent paper in Current Biology, IGTRCN Participant Arnaud Martin and colleagues use Cas9 gene editing technology to study the development of the crustacean Parhyale hawaiensis.  In this study by Martin et al., the specific morphology of serially homologous […]

Cas9-Mediated Gene-Drive In Mosquitoes

Gantz and Bier who demonstrated the fundamental principles of a Cas9-based gene drive system using Drosophila melanogaster in a publication earlier this year have recreated that system in the mosquito Anopheles stephensi with the help of collaborators.  Gantz et al. […]

Harmonia axyridis, 19-spot form

Sawfly and Ladybird Beetle Gene Editing

Hatakeyama et al (2015) have successfully used gene editing technology in Athalia rosae (sawfly) and Harmonia axyridis (ladybird beetle), enlarging the range of insects in which these technologies have been applied.  These results are reported in Insect Molecular Biology. Hatakeyama […]

"Papilio machaon MHNT CUT 2013 3 11 Cahors Female" by Didier Descouens - Own work. Licensed under CC BY-SA 4.0 via Commons - https://commons.wikimedia.org/wiki/File:Papilio_machaon_MHNT_CUT_2013_3_11_Cahors_Female.jpg#/media/File:Papilio_machaon_MHNT_CUT_2013_3_11_Cahors_Female.jpg

CRISPR/Cas9 Gene Editing in Papilionid Butterflies

Li et al (2015) recently published an exciting paper on butterflies genomics and functional genomics . Li et al have worked towards producing high quality genomes for extremely heterozygous and closely related butterflies P. xuthus and P. machaon. Further, they […]

Cas9 + sgRNA

CRISPRscan – A Tool Aiding Selection of CRISPR-Cas9 gRNAs

Just published online in Nature Methods, Moreno-Mateos et al report testing the activities of >1200 gRNAs in zebrafish embryos and used the results to create an algorithm for predicting gRNA efficacy. The advent of the CRISPR-Cas9 system has revolutionized genome […]

Basics of Cas9 Activity

Cas9 Gene Drive & Classical Biological Control

Webber et al have published an Opinion essay in PNAS concerning the growing interest in using engineered endonucleases (Cas9 in particular) to create gene drive systems to combat invasive species. Homing endonucleases are well known and well studied site-specific endonucleases […]

Structure of a TALE binding to DNA

Optimized TALEN Application and Screening in Drosophila melanogaster

Lee et al 2015 provide a detailed methodology for gene editing using TALENs in Drosophila melanogaster. While TALEN use is relatively well established in D. melanogaster, fine tuning the injection concentrations of designer nucleases allows for the maximum efficiency in […]

Powerful Genetic and Genomic Toolbox of Nasonia Wasps

Jeremy Lynch (2015) has published a nice overview of the genetic/genomic tools currently available for Nasonia species. Insects in the order of Hymenoptera are emerging as new genetic and genomic tools for evolutionary biology, development, and behavioral ecology. Among over […]

Electroporation Theory

Electroporating the CRISPR/Cas9 System

Qin et al. (2015) describe their successful efforts to use electroporation technology to introduce CRISPR/Cas9 system components into mouse embryos and while not exactly insect biology their motivations for pursuing this approach are shared by many insect biologists with an interest […]

CRISPR/Cas9 Knock-in Technology

Cas9 Against RNA Targets In Vivo

Price et al (2015) have recently published a paper in PNAS in which they report that Cas9 can be used as a RNA-targeting system. Clustered, regularly interspersed, short palindromic repeats-CRISPR associated (CRISPR-Cas) systems are a diverse collection of adaptive immune […]

CRISPR-Cas9 mediated “Mutagenic Chain Reaction”

A recent paper in Science by Gantz and Bier (2015) investigated the potential of utilizing the CRISPR-Cas9 system as, essentially, a programmable homing endonuclease to generate homozygous loss-of-function (LOF) mutants. Advances in genome editing have allowed for the directed generation of […]

Exchangeable Cassettes Controlled by Endogenous Genes

Two recent publications, Gnerer et al. and Diao et al., address the issue of recreating the fine transcriptional patterns of endogenous genes with binary expression systems in insects. Binary expression systems are extremely powerful tools for controlled gene manipulation. The […]

Pulling Recent CRISPR/Cas9 Work in Drosophila Together

Xu et al. review the recent history of using CRISPR/Cas9-based technologies in Drosophila melanogaster. Within the last two years there have been numerous publications describing the use of CRISPR/Cas9-based technologies in Drosophila melanogaster.  These last two years have been a time […]

Comparing TALE- and dCas9-Based Designer Transcription Factors

Genome editing with programmable nucleases using transcription activator-like effector nucleases (TALENs) or RNA-guided clustered regularly interspersed short palindromic repeat (CRISPR) associated protein (Cas9) have become popular and important technologies. These systems can be modified to carry other functional protein domains […]

IGTRCN Trainees – Fall 2014!

The IGTRCN is working to diffuse knowledge and technology from those who ‘know’ and ‘have’ to those who do not but need to. The Peer-to-Peer Training Fellowships are intended to facilitate the process by providing modest resources to encourage interactions. […]

Delivering gene-editing proteins in vivo using a new strategy.

Delivering genetic technologies to appropriate cells at the appropriate times is, for many insect systems, the biggest obstacle to the widespread use of these technologies. Microinjecting developing embryos with DNA, RNA or protein remains the dominant mode of delivery in […]

Plasmids for Rapid and Versatile Genome Editing

As is the case for many other organisms, CRISPR has rapidly become the method of choice for targeted genome modification in insects. Much of the method development has been taking place in the model organism Drosophila melanogaster, where, in little […]

Cas9 with functional domains highlighted in relation to target DNA and guideRNA

CRISPR/Cas9 for RNA Cleavage

The CRISPR/Cas9 system is quickly becoming the most versatile method for modifying DNA targets, but researchers seeking equivalent control against RNA transcripts have been left behind. In a new paper by O’Connell et. al, (2014) the authors describe a clever […]

“CHOPCHOP”ing with CRISPRs and TALENs: A New Web Resource for Genome Editing Design

With the growing influence and applicability of genome editing technologies, TALENs and more recently CRISPRs, offer genetic capabilities to an ever growing list of organisms. In turn, as more and more researchers become interested in using these technologies, a common […]

vasa Cas9 expressing Drosophila. From Xue et al. 2014

Vasa Cas9 Experession Yields Good Mutation Rates in Drosophila

Xue and colleagues report efficient knock-out and knock-in manipulations of the Drosophila genome with a Cas9 transgenic system. Others have made similar observations.  Xue et al. report the germline mutational rate ranging from 14% to 95%. They also demonstrated the […]