In the war against the mouse in the islands of the house invasion, the learned people use the rodent’s own genes against it.
By introducing the right tweaks to a few hundred genetically modified mice, researchers were able to report the invasion of the island’s mouse population to extinction in about 25 years, Nov. 15. Journal of the Academy of Sciences. The trick is adding mutations to a section of mouse DNA that is inherited much more frequently than it should be.
Scientists have created similar extra-hereditary genes — called gene drives — in the lab. The ropes are designed to cross over the top or all of the animal’s offspring in the usual place, and in stipulation they make those offspring infertile. Scientists have engineered a gene to reduce the population of mosquitoes and fruit flies (SN: 12/17/18).
But mammals are another story. Scientists have previously summarized the driver genes that are passed on late in mice about 80 percent of the time (SN: 1/23/19). But the driver was not strong enough to stop the fast crowd.
Luckily, nature handled it. A haplotype is a naturally occurring group of genes that is transmitted through a replication unit. The house mouse genomeMouse muscle) has a special haplotype, which is called t a haplotype that is passed on to offspring more than 95 percent of the time, as opposed to the typical 50 percent.
This kind of natural drive has benefits, says Anna Lindholm, a biologist at the University of Zurich who was not involved in the study. “It evolves naturally and continues to exist in the wild, and we don’t resist it in wild nations,” he said. It is not even found in the species muscle probably meaning it is not invasively spread to other rats.
Paul Thomas and his colleagues set up a molecular strategy to attack theaemon t haplotype with cut and paste molecular is called CRISPR/Cas9 (SN: 8/24/16). CRISPR used to insert a sequence of genes for the CRISPR tool itself t haplotype When a male mouse changes bearing t haplotype merges with the female, inserted genes to the CRISPR tool spring into action. It uses a special genetic guide to target and inactivate the gene for the hormone prolactin – rendering any female mice infertile.
The best part is natural t The haplotype can also cause male infertility, says Thomas of the University of Adelaide in Australia. Males with two copies—the homozygous male—are not representative at all.
“If he could take it” t spread through the population, you could have homozygous males being sterile,” he said. “And by adding the CRISPR element on top of that, we get homozygous females that are also sterile.”
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To know how well t mice form a haplotype on an island where mice are wreaking havoc on biodiversity, scientists used a computer simulation of an island with 200,000 mice. The team found an additional 256 mice with CRISPR-modified mice t haplotype can successfully drive the mouse population to a number of about 25 years. Even without CRISPR, the mice added normal t haplotype could reach the population in about 43 years.
But the models are not mice. In the final test, Thomas and his colleagues made the model a reality. The team has changed t haplotype in a small group of mice in the lab and used genetic tests to show that those mice will pass on their new genetics 95 percent of the time.
“This is clever, to overbuild” t haplotype natural drive system and the use of CRISPR, not to spread the device, but to destroy the genes necessary for female fertility”, says Lindholm. “This is a great step forward in the development of new tools to control invasive mouse populations”.
The next step, Thomas says, is to test the effects of real populations of mice in secure enclosures, if the .dead gene is to be explored. t can stop mice from breeding. Scientists also want to make sure that any engineered mice released into the wild have some sort of safety mechanism in place, so the mice crawl elsewhere.
The final version might be to sneer at the small changes that occur on only one island, where Thomas suggests the plague of humans has been removed. If the mouse had escaped to the continent, its mutated gene would not have been effective in local mice. Scientists also want to consult with people living in the area, as officials did when genetically modified mosquitoes were released in Florida (SN: 5/14/21).
Finally, he notes that the inhabitants of the island have been hostile for 25 years. “We would love to see CRISPR work faster,” he said. “It’s also a work in progress.”
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