These authors contributed equally to this work.
- Jackson Champer &
- Anna Buchman
Department of Entomology, University of California, Riverside, Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, California 92521, USA.
- Jackson Champer,
- Anna Buchman &
- Omar S. Akbari
Competing interests statement
The authors declare no competing interests.
Jackson Champer is a postdoctoral scholar in the Department of Entomology at the University of California, Riverside, USA. He is interested in developing and mathematically modelling new gene drive systems and creating novel architectures for existing systems.
Anna Buchman received her B.S. and M.S. at Sam Houston State University in Huntsville, Texas, USA, and her Ph.D. at the California Institute of Technology (Caltech) in Pasadena, USA. She is currently a postdoctoral scholar in the Department of Entomology at the University of California, Riverside, USA, where she is working to develop Medea systems outside the fruitfly and is also investigating novel ways to generate chromosomal translocations for use as gene drives.
Omar S. Akbari
Omar S. Akbari is an assistant professor in the Department of Entomology at the University of California, Riverside, USA. He was previously at the California Institute of Technology (Caltech), Pasadena, USA, and worked on developing Medea and underdominance-based drive systems. His research group is inspired by synthetic biology and is currently working to further develop several types of gene drive systems in multiple organisms.
- Gene drive
Initially coined to describe the process of stimulating biased inheritance of particular genes to alter entire populations, the term is now increasingly used to describe the actual synthetic genetic element designed to increase in frequency over time in a population. In this Review, this term is inclusive of all types of gene drive systems discussed and is used interchangeably with the term 'selfish genetic element'.
- Payload genes
Genes that can be linked to a gene drive to spread a desirable trait throughout a population.
(Clustered regularly interspaced short palindromic repeats–CRISPR-associated 9). A gene editing technology originating in bacteria that consists of an endonuclease (Cas9) and a guide RNA that can target and modify user-defined DNA and RNA sequences with great accuracy.
- Resistance alleles
Alleles that are resistant to a drive system, preventing it from spreading. They can originate from mutations or errors in replication or DNA repair resulting from the gene drive, or they can exist in a population before release of the gene drive.
- RNA-guided endonucleases
Nucleases such as CRISPR-associated 9 (Cas9) or Cpf1, that are directed by guide RNAs to target and cleave specific nucleotide sequences.
A programmable RNA-guided endonuclease from bacteria that cleaves DNA, generating staggered double-stranded breaks.
The process by which an endonuclease cleaves a specific DNA target sequence and copies itself, or 'homes', into this target sequence. Homing utilizes the cell's homology-directed repair (HDR) machinery, which relies on sequences that flank the endonuclease and that are homologous to either side of the target sequence. The ultimate result of homing is to generate an exact copy of the endonuclease in the target sequence.
The ability to completely remove a gene drive system from a population via the release of wild-type organisms.
The ability to replace an existing gene drive system with another system.
- Modification drive
A gene drive designed to spread genomic changes and/or genetic payloads throughout a population, thereby modifying the population.
- Suppression drive
A gene drive designed to reduce or eliminate the population of its target organism.
- Homing endonuclease genes
(HEGs). Naturally occurring types of gene drive that are composed of an endonuclease encoded either as a freestanding gene within introns, as a fusion with host proteins, or as a self-splicing intein, with the ability to home into the opposite chromosome, resulting in more than half of offspring inheriting the HEG.
- Homing efficiency
The rate at which a homing-based drive gene becomes successfully copied onto the opposite chromosome via homology-directed repair.
- RNA-guided drive
Any engineered drive system that utilizes an RNA-guided endonuclease to bias its inheritance and increase in frequency in a population.
In an X-Y heterogametic species, an X-Shredder is a type of gene drive that cleaves the X chromosome at multiple places during meiosis in males, thus destroying it. Because of this, most or all of the viable sperm will contain Y chromosomes, resulting in biased sex ratios in favour of males and, over time, suppression of the population owing to lack of females.
- Sterile insect technique
A method for temporarily suppressing target populations, whereby overwhelming numbers of mass-produced sterile insects are released to mate with wild-type insects.
A species containing different sex chromosomes between males and females. Humans are an example of a heterogametic species; Y chromosomes are found only in males.
- Bistable switch
A phenomenon in which a certain threshold frequency for a gene drive system defines its eventual fate in a population. If the frequency of individuals with the gene drive in a population is above that threshold, it will spread and eventually reach fixation. If it is below that threshold, it will be eliminated from the population.
A type of asexual reproduction in which the offspring develop from an unfertilized egg.
- Cytoplasmic incompatibility
A phenomenon that results when sperm and eggs are unable to form viable offspring.
A class of genetic elements that can insert themselves into different locations in a genome.
Small extra chromosomes to the standard complement that occur in many organisms.