> All of this changed in the last decade with the advent of CRISPR-Cas9, a gene-editing system borrowed from microbes that enables the generation of genetically manipulated transgenic animals in a matter of months rather than years. Rather than modify one or two targets, the potential to modify dozens of genes to make the pig organs resemble human organs — and then throw in some modifications to downregulate immune responses in the organs themselves — became technically simple.
