Scientists from the Salk Institute – a biological research organisation in California – have taken cells from pigs and people to create an embryo that was then inserted into a female pig. As part of initial experiments, several different types of human cells were inserted into pig embryos in petri dishes to determine which cells were the best match for the pig embryo. The human cells which worked best with the pigs’ were infant ones which have the potential to develop into all adult cell types – known as a pluripotent cell. The cells that survived eventually formed a human/pig embryo, which were then injected into female pigs and allowed to develop for around a month.

GETTY Scientists have created a human-pig embryo

GETTY Pigs' hearts are similar to humans

Lead author of the research, Izpisua Belmonte, said: “This is long enough for us to try to understand how the human and pig cells mix together early on without raising ethical concerns about mature chimeric animals.” However, even the strongest surviving cells were relatively weak, but at this stage it is more of a trial and error process, the scientists pointed out. Dr Belmonte: “At this point, we wanted to know whether human cells can contribute at all to address the ‘yes or no’ question.

Juan Carlos Izpisua Belmonte Scientists merging human and pig cells

“Now that we know the answer is yes, our next challenge is to improve efficiency and guide the human cells into forming a particular organ in pigs.” To do this, the researchers will turn to genetic modification to edit pig genomes so that they can fit human cells in.

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The team are now on the brink of creating a genetic chimera – an organism made up of cells from multiple species’ DNA – that is part human, part pig. The hope is that the scientists will eventually be able to grow organs in pigs that will be suitable for human use via transplants. With a global organ donor shortage, scientists have identified pigs as an ideal candidate to help as their organs, specifically the heart and kidneys, are very similar to that of a humans.

GETTY Could it lead to a Frankenstein-style monstrosity?