Monday, June 05, 2017 by Isabelle Z.
When you choose to interfere with nature, you should be prepared for results that are far from natural. That’s the message of a new study out of the Columbia University Medical Center, where researchers are warning scientists that the CRISPR-Cas9 gene editing technology results in unintended mutations that could go undetected.
As a relatively new technology, there are a lot of unknowns when it comes to gene editing. Known for being precise, efficient, and quick, the CRISPR-Cas9 method has shown some promise. For example, scientists have used it to edit HIV out of some living organisms and modify mosquitoes to get rid of malaria.
However, this is far from a perfect science, and now a study published in the journal Nature Methods shows that it can cause unintended mutations in genomes. This is particularly concerning when you consider the fact that clinical trials of using CRISPR on humans are already underway in places like China.
Columbia University Medical Center’s Stephen Tsang, who co-authored the study, urged the scientific community to consider the possible hazards of off-target mutations. In the study, his team sequenced mice genomes that had previously been subjected to the CRISPR technology in order to cure blindness. They found 1,500 single-nucleotide mutations and more than 100 bigger deletions and insertions when they examined the genomes of two of the subjects in depth.
The scientists are pressing for a more accurate way to check for mutations, insertions and deletions in genomes, such as using whole-genome sequencing rather than depending on computer algorithms alone. Computer algorithms did not detect any of the mutations that were discovered in the study, which is startling.
Study co-author Alexander Bassuk of the University of Iowa concurred, saying that the predictive algorithms work well when CRISPR is used on tissues or cells in a dish, but it has serious shortcomings when used on living animals. With this method, a computer model is used to predict where mutations might occur, and then only those areas are checked in depth to see if any unintended changes took place in the genetic code.
The technology has been particularly popular in China, where the government and some corporations are making huge investments in CRISPR. In fact, Chinese scientists say they were the first to make a type of wheat that is resistant to a fungal disease. They also claim to have created more muscular dogs and leaner pigs. What they often fail to mention, however, is the fact that 30 of the 32 pigs they subjected to the technique died prematurely, showing that even the simplest of genetic tweaks can have a big impact on the animal throughout its lifetime.
While few people would argue with the importance of finding a way to cure cancer, not all uses of CRISPR are ethical. For example, the Chinese scientists who found a way to make dogs more muscular, jump higher and run faster are considering using the technology to benefit the military and police by creating stronger dog breeds. If that happens, it’s only a matter of time before they start using it to alter human DNA to create “better” police officers and soldiers.
Other scientists are eyeing the use of the technology to bring back extinct species, with one team of researchers saying they could use it to bring the woolly mammoth back from extinction in the next two years. A Harvard University research team wants to create a hybrid elephant/mammoth embryo with a view to saving the endangered Asian elephant from extinction. Could the reemergence of dinosaurs be right around the corner?