title: A CRISPR-Cas9 sex-ratio distortion system for genetic control.
abstract: Genetic control aims to reduce the ability of insect pest populations to cause harm via the release of modified insects. One strategy is to bias the reproductive sex ratio towards males so that a population decreases in size or is eliminated altogether due to a lack of females. We have shown previously that sex ratio distortion can be generated synthetically in the main human malaria vector Anopheles gambiae, by selectively destroying the X-chromosome during spermatogenesis, through the activity of a naturally-occurring endonuclease that targets a repetitive rDNA sequence highly-conserved in a wide range of organisms. Here we describe a CRISPR-Cas9 sex distortion system that targets ribosomal sequences restricted to the member species of the Anopheles gambiae complex. Expression of Cas9 during spermatogenesis resulted in RNA-guided shredding of the X-chromosome during male meiosis and produced extreme male bias among progeny in the absence of any significant reduction in fertility. The flexibility of CRISPR-Cas9 combined with the availability of genomic data for a range of insects renders this strategy broadly applicable for the species-specific control of any pest or vector species with an XY sex-determination system by targeting sequences exclusive to the female sex chromosome.
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Roberto
authors.initials: R
authors.lastname: Galizi
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hammond
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Kyros
authors.initials: K
authors.lastname: Kyrou
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.|Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy.
authors.forename: Chrysanthi
authors.initials: C
authors.lastname: Taxiarchi
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Federica
authors.initials: F
authors.lastname: Bernardini
authors.affiliation: Department of Life Sciences, Imperial College London, Silwood Park, Ascot SL5 7 PY, UK.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: O'Loughlin
authors.affiliation: Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy.
authors.forename: Philippos-Aris
authors.initials: PA
authors.lastname: Papathanos
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Tony
authors.initials: T
authors.lastname: Nolan
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Windbichler
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Crisanti
mesh_terms: D000818:Animals; D000852:Anopheles / Q000235:genetics*; D064113:CRISPR-Cas Systems; D004772:Entomology / Q000379:methods*; D008297:Male; D008967:Molecular Biology / Q000379:methods*; D009032:Mosquito Control / Q000379:methods; D011995:Recombination, Genetic; D012270:Ribosomes / Q000235:genetics; D012744:Sex Ratio