Human-pig chimeras and the history of xenotransplantation

Researchers in California have created human-pig chimeric embryos as part of a project to grow human organs for transplantation; while it may make many people uncomfortable, we have been trying to use pigs for parts for nearly 200 years.

Being held prisoner by the Bedouin might not seem like a great place to do research, but for Irish surgeon Dr Bigger it was an experience full of opportunities. In 1835 he managed to transplant a cornea into a blind pet gazelle from a wounded wild deer; the transplantation seemed to be a success, and it inspired him to seek out similar operations, to see if they could promise a cure for blindness in humans. He tried transplantation experiments on many rabbits, and came across one instance where a wolf's cornea had been successfully implanted into a pet pointer dog (which promptly ran away and lived wild in the woods for three months). Writing up these experiments and observations in 1838, Bigger suggested that a pig's cornea would be the best possible match for a human being.