MSGID: 1:317/3 6270b046   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Self-eliminating genes tested on mosquitoes    
    Temporary transgenes may reduce risks associated with invasive genetic   
   elements    
      
     Date:   
         May 2, 2022   
     Source:   
         Texas A&M AgriLife Communications   
     Summary:   
         Scientists have tested a technology to make temporary genetic   
         modifications in mosquitoes. The modifications self-delete over   
         time.   
      
      
      
   FULL STORY   
   ==========================================================================   
   Texas A&M AgriLife Research scientists have tested a technology to   
   make temporary genetic modifications in mosquitoes. The modifications   
   self-delete over time.   
      
      
   ==========================================================================   
   Texas A&M AgriLife Research scientists published an article detailing   
   a mechanism to make temporary genetic alterations to mosquitoes. (Stock   
   photo) The mechanism to make temporary genetic changes could be important   
   for scientists hoping to modify mosquitoes in ways that help manage   
   populations and prevent vector-borne diseases like West Nile virus   
   without permanently altering wild populations' genetic makeup.   
      
   An article detailing their test results, "Engineering a self-eliminating   
   transgene in the yellow fever mosquito, Aedes aegypti," was published in   
   Proceedings of the National Academy of Sciences' PNAS Nexus. The authors,   
   Zach Adelman, Ph.D., and Kevin Myles, Ph.D., both professors in the Texas   
   A&M College of Agriculture and Life Sciences Department of Entomology,   
   describe a method for programming the removal of edited genes within   
   populations of mosquitoes over multiple generations.   
      
   The method is a first step toward building safeguards for genetic   
   modifications developed to control populations of mosquitoes and the   
   vector-borne diseases they carry. The idea is to test proposed changes   
   without making the changes permanent and without the risk of transmitting   
   them to wild populations, Adelman said.   
      
   "There are lots of ecological questions we don't know the answers to,   
   and when you are testing 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 happens, we're just out of luck,'" Adelman   
   said. "This mechanism is about how we get back to normal whether the   
   experiment does or doesn't come out the way we expect."  Adelman and   
   Myles are co-directing 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 To prevent mosquito-transmitted   
   diseases, approaches based on genetic control of insect populations are   
   being developed, Adelman said. However, many of these strategies are   
   based on highly invasive, self-propagating transgenes that can rapidly   
   spread the trait into other populations of mosquitoes.   
      
   Keun Chae, Ph.D., a post-doctoral researcher in Adelman's group, led   
   the experiments in Aedes aegypti mosquitoes, which are known vectors   
   of diseases.   
      
   Taking advantage of a form of DNA repair, Chae engineered a duplicated   
   genetic code region along with two genes for fluorescent proteins into   
   the middle of a gene important for eye pigment.   
      
   The result was a white-eyed mosquito, and also red and green fluorescence   
   in the eyes and body. When combined with a site-specific nuclease, which   
   is essential for many aspects of DNA repair, they 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 proof of principle that scientists can do two   
   important things -- remove transgenes placed in mosquitoes and repair   
   disrupted genes.   
      
      
      
   ==========================================================================   
   "Many groups are developing genetic methods for mosquito population   
   control," Adelman said. "Our method provides a braking system that can   
   restore sequences in the wild."  Self-editing transgenes could be leap   
   for genetic research Myles said creating this self-editing transgene is   
   the first step in a longer process. The mosquito genome is not easy to   
   manipulate, and the breakthrough is the culmination of around six years   
   of experimental work.   
      
   But this first publication starts to address concerns about genetic   
   modification in wild populations, he said. As genetic modification   
   technology advances, Adelman and Myles believe this mechanism will allow   
   researchers to evaluate the effects of changes more safely within the   
   environment and on animals other than mosquitoes.   
      
   "These are highly conserved genetic pathways, and there is every reason   
   to believe this method could be applied to a diverse range of organisms,"   
   Myles said.   
      
   Both scientists are looking forward to expanding the application of their   
   discovery in the context of highly active gene drive. They hope their   
   method will be useful for geneticists and in pushing the boundaries of   
   genetic research.   
      
      
   ==========================================================================   
   Story Source: Materials provided   
   by Texas_A&M_AgriLife_Communications. Original written by Adam   
   Russell. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Keun Chae, Chanell Dawson, Collin Valentin, Bryan Contreras, Josef   
         Zapletal, Kevin M Myles, Zach N Adelman. Engineering a   
         self-eliminating transgene in the yellow fever mosquito, Aedes   
         aegypti. PNAS Nexus, 2022; DOI: 10.1093/pnasnexus/pgac037   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220502131346.htm   
      
   --- up 9 weeks, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 129/330 331 153/7715 218/700   
   SEEN-BY: 229/110 111 317 400 426 428 470 664 700 292/854 298/25 305/3   
   SEEN-BY: 317/3 320/219 396/45   
   PATH: 317/3 229/426