I've often wondered about Cystic Fibrosis and DNA editing. For people with two copies of the variant gene, they get the disease. But there are indications that having one copy of it can bring benefits (https://en.wikipedia.org/wiki/Heterozygote_advantage).
So what if the optimum for humans is to have both variants? It would seem appropriate to move the newer CF gene variant to a different place on the chromosome so that doesn't need to displace the original gene. I imagine nature may eventually figure this out, but embryonic DNA editing could bring it about sooner. Of course this is speculative on my part and people would obviously debate taking such action even if the science really suggests it's a good idea.
So what if the optimum for humans is to have both variants? It would seem appropriate to move the newer CF gene variant to a different place on the chromosome so that doesn't need to displace the original gene. I imagine nature may eventually figure this out, but embryonic DNA editing could bring it about sooner. Of course this is speculative on my part and people would obviously debate taking such action even if the science really suggests it's a good idea.