Chimeric pigs could grow human organs

Injecting human stem cells into pig embryos that have been genetically modified to lack specific organs could produce an unlimited supply of human organs for transplant

CRISPR-Cas9 gene editing DNA-cutting enzyme called Cas9 acts like molecular scissors to snip through DNA of newly fertilised pig embryo

Pig DNA

Cas9

gRNA

Small gRNA molecule guides scissors to specific sequence of DNA to make cut

Deleting key gene results in pig foetus unable to grow particular organ

Organ transplantation Target organ is tranplanted from pig to patient

Human induced pluripotent (iPS) stem cells – capable of becoming any cell type – are obtained from patient

Stem cells

Human iPS cells are injected into embryos at blastocyst stage. Human-pig chimeric embryos are implanted
into womb of sow

Blastocyst

Pig embryo develops normally but target organ is made out of patient’s cells

CRISPR stands for “clustered regularly interspaced short palindromic repeats”

Sources: University of California, Davis, Royal Society of Biology