Frankenmouse: A Story of Chimaeras

You may have heard of the Chimaera from Ancient Greek mythology. With the head and body of a lion, a snake as a tail, and a goat head on its back, the Chimaera is indeed a fearsome creature. 

A Greek silver coin depicting the Chimaera, by Ancient Art & Numismatics via Flickr.


Today, we use this word to describe organisms that are made up of cells from at least two different species. Scientists have considered creating human-animal hybrids for decades; however, the media and the public have often spoken out against such creations. What are the considerations that we have to keep in mind to avoid the follies of Dr. Frankenstein?


De-Livering Life-saving Treatment

What if I told you that we could save thousands, even millions of lives, through the creation of animal-human hybrids? I am of course talking about the contentious issue of organ donations. Right now, there are 1,400 Australians who are in dire need of an organ transplant and a further 11,000 are on dialysis – people whose lives would improve immensely if they received a transplant. So, how can we increase the supply of available organs? One way would be to increase the rate of voluntary organ donation. Keep in mind that your organs are not freely available – you still need your lungs to breathe! Animal-human hybrids could be a sound solution to this crisis.

A human heart, by David Lebovitz via Flickr.



Organ rejection is a fact of life for many recipients, and they must take anti-rejection pills for the rest of their lives. The benefits of hybrid organs include the potential to personalise organs for each patient. By taking cells from the recipient and growing the cells in a hybrid animal, the resulting organs will not be detected by the person’s body as foreign upon transplantation. One thing to consider though, is that the field is still in its infancy. A study published in 2017 found that, out of human 100,000 cells injected into a pig embryo, only one was retained through development. However, there is good news for lab-grown organs.

A mouse embryo, by johnnyswatts via Flickr.


Chimaeras dawn in Japan

In a world-first, Japan has approved the creation of human-animal hybrid embryos – allowing researchers to bring the embryos to term on certain conditions. Animal embryos that contain human cells are now allowed to be kept alive past 14 days – and even transplanted into a surrogate animal. Through the use of stem cells, Dr. Hiromitsu Nakauchi from the University of Tokyo/Stanford University plans to create pig hybrids with human organs. These mighty cells can give rise to almost any cell type – a blessing for organ donation. There are some barriers in his research though. Tests in mice to produce a human pancreas in 2017, resulted in a pancreas made entirely of mouse cells! All things considered, we will still have to wait years before human organs can be generated and harvested in such animals.


A life for a life

Do you think the life of a pig is equal to that of a human? Is it ethical to grow animals for the sole purpose of harvesting human organs? Everyone has their own opinions and reservations about this issue, and truly there is no right answer. Considering that we already put more than a billion pigs to slaughter around the world each year, we should already be questioning our conscience. But one thing’s for certain, for every day that we delay, thousands of lives are lost to organ failure.


The murky future of animal-human hybrids is becoming clearer by the day. It won’t be long before regulations in developed nations catch up with technology. One day you might ask yourself this: would you accept an animal-raised organ if you needed it to live?

4 Responses to “Frankenmouse: A Story of Chimaeras”

  1. John Tay says:

    Thanks for the reply Wenjia!
    There is an idea that by incorporating human cells into animal embryos, they may develop to become more human-like.
    This is especially controversial if we decide to use brain cells where cognition is involved.
    We also have to consider the complexity of the host animal to use.
    The more complex and human-like animals we use – such as pigs and monkeys – the better the substitute. However, these animals also tend to be more cognizant and self-aware – raising ethical questions.
    Finding the balance is key!

  2. Wenjia LU says:

    I like your writing style! The ancient myth your tell in the first paragraph really attracts me. There are many ethic problems and interesting stories about this area. I am wondering there is any other ethics discussion about this?

  3. John Tay says:

    Thanks Aimen, I’m glad you agree with the idea!

  4. Aimen Ksiksi says:

    Excellent post! I agree completely with the logic you follow. There s a shortage of organ donors world-wide, while many extremely needy people wait on a multiple year wait list when they only have a few months to live.

    Making animal-human hybrids might be a scary thought but for the benefit of humanity it does sound attractive!