A figure showing that gene drive transmission is not Mendelian. Credit: Cutter, 2023
Using CRISPR-Cas9 technology, humans can now quickly alter the evolutionary course of animals or plants by introducing genes that can easily spread across entire populations. Evolutionary geneticist Asher Cutter suggests we call this evolutionary intervention “genetic welding”. In an opinion article published on March 28 in the journal Trends in geneticsHe argues that we must scientifically and ethically examine the potential consequences of genetic welding before we put it into practice.
“The ability to perform gene welding has only really begun to take off in the last few years, and a lot of the thinking around it has focused on what might happen in the near term,” says Cutter of the University of Toronto. “Ethically, before humans apply this to natural populations, we need to start thinking about what the long-term consequences might be on a time scale of hundreds or thousands of generations.”
In classical Mendelian genetics, we think of genes that have a 50:50 chance of being passed from parent to offspring, but this is not always the case. In a natural phenomenon known as “genetic drive,” certain genes are able to bias their transmission so that they are more likely to be inherited.
Gene welding is the human-mediated version of this — introducing genes that have an unfair advantage when it comes to heredity into natural populations. Because these genes spread so easily and quickly through populations, they lead to evolutionary change much faster than the usual slow deceleration we see from natural and artificial selection. Also, unlike natural selection, genetic drives and genetic welding can perpetuate genes that do not necessarily benefit the organisms that carry them, making it an attractive potential method for controlling problematic/invasive/disease-carrying species.
Gene welding in this way has been proposed as a tool to control populations of disease-carrying mosquitoes and invasive species. It can also be used to genetically engineer endangered species to be resistant to infectious pathogens that threaten them with extinction. “It raises the question of the extent to which humans are involved in processes that are usually beyond our control,” says Cutter.
“If ethicists, medical practitioners, and politicians decide that it is acceptable in some cases to modify the germline of humans, that would open up the possibility of genetic welding as a tool in this regard,” says Cutter. “This would open up an even larger can of worms by virtue of the fact that genetic welding can alter an entire population or species, not just a few individuals who choose to have surgery.”
Although it can be difficult to empirically assess the long-term effects of genetic welding, Cutter says that thought experiments, mathematical theory, computer simulations, and conversations with bioethicists can all play important roles, as can experiments in organisms with short lifespans and reproduction. The rapid.
more information:
synthetic gene driving as an anthropogenic evolutionary force, Trends in genetics (2023). DOI: 10.1016/j.tig.2023.02.010
the quoteWhat should we call evolution driven by genetic engineering? Genetic Welding, Researcher Says (2023, March 28) Retrieved March 28, 2023 from https://phys.org/news/2023-03-evolution-driven-genetic-welding.html
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