Additionally, for the moment, Crispr is not absolutely safe. In the Chinese experiment of 54 embryos only four were deemed a success. But even those had some off-target mutations unintended by the scientists.
In the meantime, critics argued that the experiment would pave way to ‘designer babies’ and a new era of eugenics, where the individual with the best genes survives and dominates the genetically inferior.
Plus, the off-target mutations proved that the technology is unsafe to tweak human embryos. On Tuesday, a research team at the Massachusetts Institute of Technology (MIT) announced that they developed a technique to lower the chances of having off-target mutations with Crispr.
MIT scientists explained that they modified a protein to lower the risk of those effects. But the long-term goal is to bring error rate to zero. If Crispr produces too many errors, the genetic tool is clearly unreliable and unsafe to use on humans. This is why many researchers perceive the tool as unethical.
Now one question remains. If Crispr will become absolutely safe, would that make the technique ethical? During this Tuesday’s meeting, scientists weren’t able to provide a clear answer to that.
Josephine Johnston of the Hastings Center acknowledged that safety is an important topic to all Crispr researchers, but the ‘other kinds of concerns’ related to the technology are not that easy to talk about.
Johnston also said that the concerns had a social nature, rather than scientific one. Many people see the technique as being unethical because there is no consent of the babies and humans should not play God with their own genes.
The researcher noted that as safety concerns fade out, the ethical concern become more clear.
MIT scientists altered Cas9, a protein that tries to match a DNA fragment against a piece of its guide RNA, to result in fewer mismatched genetic fragments. Often Cas9 thinks that a mismatched DNA fragment is its target even though up to five letters in the guide RNA are mismatched. This is how mutations occur.
After MIT’s work, Crispr would only produce errors at a one in 300 trillion letters rate, George Church of Harvard who was not involved in the study believes. Researchers now strive to bring that rate closer to the rate of natural genetic mutations in humans.
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