Scientists Research An Even More Powerful Technique for Genetically-Modifying Mosquitos

The BBC reports on "the next generation of genetic modification technology" — which goes beyond simply introducing a "lab-tweaked gene" into an organism. Instead it introduces a "gene drive" — a lab-tweaked gene "that targets and removes a specific natural gene." if an animal (parent A) that contains a gene drive mates with one that doesn't (parent B), then in the forming embryo that starts to combine their genetic material, parent A's gene drive immediately gets to work. It recognises the natural gene version of itself in the opposite chromosome from parent B, and destroys it, by cutting it out of the DNA chain. Parent B's chromosome then repairs itself — but does so, by copying parent A's gene drive. So, the embryo, and the resulting offspring, are all but guaranteed to have the gene drive, rather than a 50% chance with standard GM — because an embryo takes half its genes from each parent. Gene drives are created by adding something called Crispr, a programmable DNA sequence, to a gene. This tells it to target the natural version of itself in the DNA of the other parent in the new embryo. The gene drive also contains an enzyme that does the actual cutting. It is hoped that gene drives can be used to greatly reduce the numbers of malarial mosquitos, and other pests or invasive species.... One organisation at the forefront of this is Target Malaria, which has developed gene drives that stop mosquitos from producing female offspring. This is important for two reasons — only the females bite, and without females, mosquito numbers will plummet. The core aim is to greatly reduce the number of people who die from malaria — of which there were sadly 627,000 in 2020, according to the World Health Organization. It could also slash the economic impact of the disease. With 241 million cases in 2020, mostly in Africa, malaria is estimated to cost the continent $12bn (£9.7bn) in reduced economic output every year.... One of the world's pioneering developers of gene drives is US biologist Kevin Esvelt, an assistant professor at Massachusetts Institute of Technology. He first came up with the technology back in 2013.... Prof Esvelt adds that this technology is being provided by something called "daisy chain". This is where a gene drive is designed to become inert after a few generations. Or halving its spread every generation until it eventually stops. Using this technology he says it is possible to control and isolate the spread of gene drives. "A town could release GM organisms with its boundaries to alter the local population [of a particular organism] while minimally affecting the town next door," he says. The technology has not been authorized for use "in the wild," the article points out. But there are currently no bans on laboratories researching it.

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