In Mosquitoes, a study demonstrates how temporary self-deleting transgenes are tested

In Mosquitoes, a study demonstrates how temporary self-deleting transgenes are tested ...

Scientists at Texas A&M AgriLife have tested a technique to produce temporary genetic modifications in mosquitoes. The modifications have self-deleted over time.

Scientists hoping to alter mosquitoes in ways that help manage populations and prevent vector-borne illnesses such as the West Nile virus without permanent altering genetic makeup might be crucial to determining temporary genetic changes.

InProceedings of the National Academy of Sciences PNAS Nexus, students from Arizona, Zach Adelman, Ph.D., and Kevin Myles, both professors in the Texas A&MCollege of Agriculture and Life Sciences, describe a method for removing edited genes within mosquitoes over multiple generations.

The aim of this exercise is to develop safeguards for genetic modifications to control mosquitoes and the vector-borne diseases they carry. Adelman claims the amendments should not be altered as a condition of permanent transmission and no possibility of spreading them to wild populations.

When you are using technology, you don''t want to get into a situation where you have to tell a regulatory agency or the public that if something bad happened, were just out of luck, Adelman said. This process is about how we get back to normal whether the experiment does or does not come out the way we expect.

Adelman and Myles are collaborating with a team of scientists who received a five-year $3.9 million grant from the National Institute of Allergy and Infectious Diseases to test and fine-tune the self-eliminating transgene technology.

Back to normal in a few generations

Various strategies based on genetic control of insect populations are being developed, according to Adelman. Nonetheless, many of these methods are based on highly invasive, self-propagating transgenes that may rapidly spread the trait into other mosquito populations.

Keun Chae, a post-doctoral researcher at Adelmans, led experiments in Aedes aegypti mosquitoes, which are known vectors of diseases. Chae, leveraging a form of DNA repair, created a duplicate genetic code region and two genes for fluorescent proteins into the middle of a gene important for eye pigment.

The result was a white-eyed mosquito, with a red and green fluorescence in the eyes and body. They were incorporated with a site-specific nuclease, which is essential for many aspects of DNA repair, and acted as a precise set of molecular scissors that could cut the transgene sequences. Over several generations, mosquitoes regained their normal eye pigment and lost the modified genes.

Adelman said the work is a proof of the principle that scientists can do two things at once remove transgenes placed in mosquitoes and repair damaged genes.

Adelman claims that several organizations are developing genetic methods for controlling mosquito population. Our method is a braking system that can restore sequences in the wild.

Transgenes that are self-editing might be a leap for genetic research.

Myles said that developing this self-editing transgene is the first step in a long process. The mosquito genome isn''t easy to manipulate, and the breakthrough is the culmination of over six years of experimental work.

The first document, published in March, has begun to address concerns about gene modification in wild populations, according to Adelman and Myles. This technique will allow researchers to assess the effects of changes more safely within the environment and on animals other than mosquitoes.

These are well-recognized genetic pathways, and there is no reason to believe that this approach might be applied to a wide spectrum of organisms, according to Myles.

Both scientists are looking forward to expanding the use of their discoveries in the context of a highly active gene drive. They hope their technique will be beneficial for geneticists and in pushing the boundaries of genetic research.

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