Correction of a pathogenic gene mutation in human embryos as originally seen in Nature
It’s true: science fiction has become reality. It came out today that scientists have successfully cut and paste human genes and thereby eliminating a genetic disease. Here’s what they did.
They had sperm from a man with a genetic heart condition and fertilized some eggs with it in the lab. As they did this, they used a method called CRISPR-Cas9 to delete the bad genes. Usually at this point, they would then put in a template for the DNA repair system to copy into the now damaged portion of the sperm’s DNA. But they got a surprise at this point: the sperm completely ignored the scientists’ DNA template and instead repaired itself by borrowing DNA instructions from the egg!
When the scientists had tried this previously using other methods, the repair was done using the template and they ended up with embryos that had some cells that were fixed (didn’t have the bad genes), some that weren’t fixed (still had the bad genes) and some that had even different bad genes (mutations). If the embryos of the previous methods had been allowed to mature and become people, they may or may not have the genetic disease they were trying to get rid of, may or may not have even other genetic diseases due to the new mutations and could still pass on any of those bad genes to future children. With the new method, all the bad genes are gone, there are no new mutations and there’s no chance of anything being passed on to the next generation. That’s a pretty good improvement, I’d say!
This technology is no where near ready to be applied clinically though. First of all, no country allows it yet. (The study was financed by private companies.) There are too many unanswered ethical questions. Like, what if we genetically controlled all offspring like on Krypton in the Superman legend and created an army of SuperKids? Or what if only the rich could afford the SuperKid army and they wiped out the rest of us? Or could we create laws around this to where it is only used to edit out very dangerous genetic diseases for which there is no other viable cure, like say, cystic fibrosis, early onset Alzheimer’s, or Huntington’s disease?
This revelation today has opened up more questions than it has answered. But it is a promising new field of study and very exciting, especially for those of us that work with people suffering those types of disease this new technology might one day completely eliminate!