How do gene drives work?
Gene drive is a process that promotes or favors the inheritance of certain genes from generation to generation. It is important to understand that there are many forms of gene drive – this is an umbrella term, not a single technology. While the specific term ‘gene drive’ only came into use at the beginning of the 21st century, the genetic phenomenon referred to as ‘drive’ was first recognized early in the 20th century as a natural occurrence in many organisms. Scientists first expressed the possibility of using drive systems to control pest insects in the 1950s.
Many plants and animals have two different copies of each of their genes, having inherited one from their male parent and one from their female parent. For a gene that does not exhibit gene drive, each of those copies is equally likely to be passed to the next generation. This is often referred to as Mendelian inheritance. For a gene that displays gene drive, one of those copies would be preferentially passed to the next generation. This pattern of preferential inheritance means that in a relatively short time genes displaying drive can become highly prevalent in a population.
For more information:
https://www.geneconvenevi.org/gene-drive-timeline/
https://www.geneconvenevi.org/gene-drive-defined/
https://genedrivenetwork.org/resources/factsheets/7-factsheet-whats-a-gene-drive-july-2018-2/file
https://www.pnas.org/content/117/49/30864
https://www.isaaa.org/webinars/2021/genedrivewebinar1/default.asp
Gene drive systems are a type of genetic biocontrol in which genetic variants or genetically modified forms of a target species serve as controlling agents in a way that reduces or eliminates the threat posed by the target species. In the case of gene drive technologies, the genetic variation or genetically modified form of the target species is fertile and able to efficiently pass the genetic variation responsible for the biocontrol effect to subsequent generations, so that eventually all or most of the individuals in a population will carry the variation. Like other forms of genetic biocontrol, uses of gene drive can be envisioned for public health, agriculture, and conservation.
For more information:
https://www.youtube.com/watch?v=rmwGqDw7AUc
https://www.geneconvenevi.org/gene-drive-defined/ ; https://www.ncbi.nlm.nih.gov/books/NBK379277/
Leave a Reply
You must be logged in to post a comment.
The preferential inheritance of a gene (engineered or natural) that characterizes gene drive will cause an increase in the frequency or prevalence of the gene exhibiting gene drive within the population of organisms into which it has been introduced. Depending on the characteristics of the gene drive, virtually all of the members of an interbreeding population of the target species may eventually contain the modification. The spreading of the gene drive from its initial source individual(s) of introduction through the broader population is not unlike the ripple created when a drop of water hits a calm puddle.
Leave a Reply
You must be logged in to post a comment.
Gene drives spread through mating between individuals that carry the drive system and those that don’t (wild type). All gene drive systems have the potential to spread to some extent. The defining characteristic of gene drive is preferential transmission to the next generation, and this will result in the gene drive element increasing in frequency (spreading) within the interbreeding population of the target species. Some gene drive technologies are designed with temporal or spatial limitations on the degree of anticipated spread, and therefore the gene drive is expected to remain more localized.
For more information:
https://www.who.int/publications/i/item/9789240025233
Leave a Reply
You must be logged in to post a comment.
Scientists have proposed ways to use the preferential inheritance that characterizes gene drive to develop solutions for previously intractable threats to public health, food security, and biodiversity. For example, gene drive technologies have been proposed to address problems in public health such as the transmission of arthropod-borne pathogens, problems in agriculture caused by insect pests, weeds and plant pathogens, and problems in conservation caused by invasive species.
For more information:
https://genedrivenetwork.org/resources/factsheets/7-factsheet-whats-a-gene-drive-july-2018-2/file
https://www.geneconvenevi.org/what-is-gene-drive/
https://www.youtube.com/watch?v=rmwGqDw7AUc
Leave a Reply
You must be logged in to post a comment.
Gene drive is a genetic phenomenon and is not an “invention”. The term refers to a pattern of inheritance that is found commonly in nature. Mimicking these many examples from nature that have been known for decades, scientists are working in the laboratory to engineer gene drive systems that would introduce genetic traits into certain insects or other animals or plants such that their introduction would impact populations for the benefit of public health, conservation, or agriculture.
For more information:
https://www.geneconvenevi.org/gene-drive-timeline/
Leave a Reply
You must be logged in to post a comment.
Not all gene drive-containing organisms are genetically engineered since genetic elements with drive capability occur in nature. In fact, all genomes that have been examined to date are found to contain natural gene drives. Techniques of modern molecular biology have made it possible to mimic various types of natural drives in the laboratory, and gene drive systems created using recombinant DNA technology are called engineered or synthetic gene drives.
Leave a Reply
You must be logged in to post a comment.
No. Gene drive occurs frequently in nature in many organisms without any human intervention. Genomes of all organisms contain genes that display gene drive; for example, Dr Barbara McClintock was awarded the Nobel Prize in Physiology or Medicine in 1983 for her discovery of transposons or “jumping genes” which display gene drive. Transposons now are known to be common and abundant in the genomes of all organisms and their importance and significance is well documented. Many other naturally occurring mechanisms creating preferential inheritance of genes, alleles, and chromosomes also exist. We now understand that genes which can enhance their own transmission relative to other genes in the genome (natural gene drives) are not at all uncommon.
For more information:
https://www.nature.com/articles/s41467-023-37483-z#:~:text=There%20are%20some%20outside%20the,of%20risks%20that%20may%20be
https://www.geneconvenevi.org/gene-drive-timeline/
Leave a Reply
You must be logged in to post a comment.
No. There are different types of gene drive, and some are built to lose their effect over a period of time (self-limiting drives). In this case, the modification is expected to disappear from the population in the absence of repeated releases of the gene drive-modified organism. Another type is described as “self-sustaining,” in which the heritable modification is intended to become stably established within interbreeding populations of the target species. This type has elicited concerns about irreversibility of population level effects. However, scientists currently are working on ways to halt or reverse the effects of such drives. While these methods have not yet been perfected, this is a recognized need and an active subject of research. (Also see “What do we know about gene drive hazards.”)
For more information:
https://www.geneconvenevi.org/articles/controlling-gene-drives/?utm_source=rss&utm_medium=rss&utm_campaign=controlling-gene-drives&utm_source=rss&utm_medium=rss&utm_campaign=controlling-gene-drives
Leave a Reply
You must be logged in to post a comment.
Engineered gene drive technologies currently (2023) are in the discovery phase and are only being tested in the laboratory as part of ongoing research and development efforts. No engineered drive technologies are being used outside the laboratory. However, efforts are underway to lay the technical and regulatory groundwork to support informed decisions about the potential field testing and large-scale use of gene drive technologies.
Leave a Reply
You must be logged in to post a comment.
What is the difference between genetically modified-mosquitoes and gene drive-modified mosquitoes?
Genetically modified mosquitoes are developed using genetic engineering. Gene drive-modified mosquitoes are a type of genetically modified-mosquitoes. In both cases, mosquitoes of the targeted species are modified to exhibit one or more different traits from wild type (non-modified) mosquitoes of the same species. An example of a desirable new trait would be a decreased ability of the modified mosquitoes to transmit diseases such as malaria or dengue. Modifications might involve altering the sequence of existing genes, disabling or excising of existing genes, or introducing new genes or other genetic elements within the mosquito genome.
Several genetic modification approaches are being explored, from those that will have no lasting effect on the targeted vector population after release to those that are intended to introduce a more persistent change. When not coupled to a gene drive, a gene (including any introduced genetic modification) is typically transmitted to the progeny from mating of modified with wild type mosquitoes according to the standard (Mendelian) pattern of inheritance, where each gene has a 50% chance of being passed from the parent to the next generation. If the gene or genetic modification is associated with a fitness cost (reduced competitive ability), the related trait is expected to disappear from the population over time. If the fitness cost is severe, the introduced gene(s) can disappear rapidly; this would be the case, for example, if the modification caused reduced fertility in those mosquitoes that carried it.
When coupled with a gene drive, the genetic modification is inherited preferentially. The related new trait will eventually become dominant in the population because more than 50% (sometimes almost 100%) of the progeny from matings between gene drive-modified mosquitoes and their wild-type counterparts inherit the modification.
For more information: https://www.geneconvenevi.org/gene-drive-defined/
Leave a Reply
You must be logged in to post a comment.
Gene drive is a process that promotes or favors the inheritance of certain genes from one generation to the next. Since the early 20th century, scientists have discovered several types of “selfish genetic elements” that are present naturally in the genomes of many species. These naturally occurring genetic elements are able to enhance their own transmission relative to the rest of the genes in the genome regardless of whether their presence is neutral or even harmful to the individual organism as a whole, and thus they exhibit drive and are called “natural gene drives.” Examples of natural gene drives include homing endonuclease genes found in all forms of microbial life, transposable elements found in many plants and animals, and meiotic drive also found in various plants and animals.
Synthetic gene drives utilize techniques of modern molecular biotechnology to achieve effects similar to those seen with natural gene drives in a wider range of organisms. Thus organisms carrying synthetic gene drive(s) are considered genetically engineered/modified, though the synthetic drive mechanism they carry may function very comparably to a natural gene drive. Synthetic gene drives can be used to introduce new traits into a population of organisms, such as mosquitoes or mice, over just a few generations.
For more information:https://www.geneconvenevi.org/types-of-gene-drive/
Leave a Reply
You must be logged in to post a comment.
No. CRISPR (which stands for Clustered Regularly Interspaced Short Palindromic Repeats) is a family of DNA sequences originally observed in bacteria and derived from viral DNA upon initial infection. It acts as a defense system to protect those bacterial cells during subsequent viral invasions. The CRISPR DNA sequence is transcribed within the bacterial cell to RNA, which works as a sequence specific guide for a CRISPR-associated protein (called a Cas nuclease) that cleaves viral nucleic acid in a region complementary to the CRISPR sequence, disabling the virus. There are a variety of CRISPR/Cas types with different sequence recognition and cleavage abilities.
This CRISPR-Cas system has been adapted for use as a genome altering tool by substituting specifically constructed guide nucleic acid sequences that direct the Cas protein to cut at a particular target sequence in the DNA of an organism. This system has been found to work very efficiently in many types of cells and can be used to add, remove, or alter/edit the sequence in a targeted gene in an organism’s genome. CRISP/Cas based tools are being developed as therapies for several genetic diseases. They are also being used as one method to develop synthetic gene drives.
For more information: https://www.youtube.com/watch?v=UKbrwPL3wXE
https://genedrivenetwork.org/videos#mxYouTubeR88da54c719d7acb5beb6a53f64c5214b-7
Leave a Reply
You must be logged in to post a comment.
Leave a Reply
You must be logged in to post a comment.