Scientists have used gene editing technology known as CRISPR to create chickens that have some resistance to bird flu, a new study has found.
The study suggests that genetic engineering can help reduce mortality from bird flu, a group of viruses that pose a danger to animals and humans. But it also highlights the limitations of the approach.
Some breakthrough infections still occurred, especially when genetically modified chickens were exposed to very high doses of the virus. And when scientists edited just one chicken gene, the virus adapted quickly. The findings suggest that creating flu-resistant chickens will require editing multiple genes and that scientists will need to proceed carefully to avoid driving further evolution of the virus.
The research is “proof of concept that we can make progress in making chickens resistant to the virus,” said Wendy Barclay, a virologist at Imperial College London and an author of the study. “But we’re not there yet.”
Some scientists who were not involved in the research came to a different conclusion.
Carol Cardona, an expert on influenza and bird health at the University of Minnesota, said the results illustrate how difficult it will be to engineer a chicken that can stay one step ahead of the flu, a virus that is known to evolve rapidly. In recent years, a highly lethal version of the bird flu virus, H5N1, has spread around the world, killing countless wild and farmed birds. It has also infected wild mammals and has been detected in a small number of people. Scientists are concerned that the virus could acquire mutations that help it spread more easily among humans, potentially triggering a pandemic.
Many nations have tried to eradicate the virus by increasing biosecurity on farms, quarantining infected facilities, and culling infected flocks. But the virus has spread so widely among wild birds that it has proven impossible to contain, and some countries have begun vaccinating poultry.
Gene editing “promises a new way to make permanent changes to an animal’s disease resistance,” said Mike McGrew, an embryologist at the University of Edinburgh’s Roslin Institute and an author of the new study.
CRISPR, the gene editing technology used in the study, is a molecular tool that allows scientists to make specific edits to DNA, changing the genetic code at a precise point in the genome. The researchers used it to modify a chicken gene that codes for a protein known as ANP32A, which the flu virus hijacks to copy itself.
The modifications did not appear to have negative consequences for the health of the hens.
The researchers studied samples of the virus from genetically edited birds that were infected. These samples had notable mutations, which appeared to allow the virus to use the edited ANP32A protein to replicate.
The mutated flu virus was also able to replicate even in the absence of the ANP32A protein using two other proteins from the same family. When the team created chicken cells that lacked these three proteins, the virus was unable to replicate.
Researchers are now trying to create chickens with edits in all three genes.
By: EMILY ANTHES
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/6950625, IMPORTING DATE: 2023-10-23 19:40:07
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