Mice are a mainstay in scientific research. Before big pharma poisons us with whatever they’ve cooked up to make a huge profit, they try it out on mice first. But leave it to man not to leave well enough alone…
By Egon E. Mosum
There is an old challenge question from one man to another. ‘Are you a man or a mouse?’
Even if you said ‘mouse’ you’d (genetically speaking) be about ninety percent man.
Those little squeaky mammals are a mainstay in scientific research, and before big pharma tries to poison us with whatever they have cooked up to make a huge profit, they try it out on mice first.
But leave it to man not to leave well enough alone.
Because when it comes to who’s who in the evolutionary pecking order, we are the big cheese. We like to mess with mice whenever we can, scientifically speaking.
So, the boys in the white coats and the pocket protectors decided one fine day to mix human genes with mouse genes to see what would happen.
Steamboat Willie had some surprises in store.
A 2017 article in the publication of the National Review of Genetics tells us ‘For decades, the laboratory mouse (Mus Musculus) has been the preferred model organism for the study of human biology and diseases. Humans and mice share a very similar genetic background, and around 90% of both genomes can be partitioned into regions of conserved synteny.’[1]
That’s fancy science talk for they are pretty much the same.
Now while it was Walt Disney that first tried to humanize a mouse in two dimensions about ninety-seven years ago when Steamboat Willie appeared, these days we are trying to do pretty much the same thing in three dimensions in the laboratory.
In 2020, a ‘team of researchers injected 10 to 12 human stem cells into developing mouse embryos. Within 17 days, those stem cells developed into millions of mature cells, including human red blood cells and eye cells.’
What was produced? ‘These human-mouse chimeras exhibited 4% human cells.’
One may smell a rat when it comes to potential future ethical problems. ‘Chimera test subjects must be human enough to serve as effective models for health research, but not so human that they qualify for protection from this research altogether.’[2]
We may envision a ‘rats have rights’ movement one day, and that is not being flip, it is being future oriented.
That genetic four percent human mouse was five years ago from this writing, and perhaps one of those future rat rights may be freedom of speech, because this year, scientists have put a language gene in a mouse.
‘Mouse pups that had the human version of the language gene showed different vocalization patterns from their buddies with the usual version mice have. When calling for their mother, their squeaks were higher pitched and featured a different selection of sounds than usual.’[3]
With current research, we can not only enlarge a mouse’s mouse vocabulary, we can make them smarter.
In 2025, scientists added some human genes to mice and ‘the addition of human genes increased average brain size by 6.5%, boosting neuron production and expanding the brain’s outer layer.’[4]
If all of this has you thinking of the movie ‘The Island of Doctor Moreau’ you might be on to something. H.G. Wells wrote the 1896 novel of a doctor experimenting with human animal hybrids, and it didn’t turn out all that well.
One hundred and twenty-nine years later, we have gone from science fiction to science fact, and that must give us pause.
Where there is controversial medical research, legal ramifications are often not far behind.
While no law has yet passed as of this writing, there was a proposed bill in Congress called the Human-Animal Chimera Prohibition Act of 2023.
The bill sought to criminalize the creation of prohibited human animal chimera, forbade the transfer of human embryos into a non-human womb, and vice-versa, and to transport or receive for any purpose a prohibited human-animal chimera.[5]
A similar bill was introduced into Congress in March of 2025.[6]
There has been a history of trying to pass these types of laws in our legislature in the twenty first century, but so far, no dice, mice.
WHY YOU SHOULD CARE
We need mice for medical research. ‘Mice and rats have long served as the preferred species for biomedical research animal models due to their anatomical, physiological, and genetic similarity to humans. Advantages of rodents include their small size, ease of maintenance, short life cycle, and abundant genetic resources.’[7]
Genetically altering mice facilitates research into innovations which can be eventually applied to humans. ‘Several hundred mouse stocks containing mutations have been used for a long time as models of human disease and for the study of metabolic processes.’[8]
We have reached new heights of adding human genes to mice, and we are creating ‘super mice,’ mice that are different from normal mice. We are altering their vocal patterns, significantly increasing the size of their brains.
Depending upon the age of the reader, it might be remembered that while in high school, one of the books we were forced to read was the 1959 story Flowers for Algernon by Daniel Keyes.
Algernon was a mouse that through surgical intervention became super intelligent. It was fittingly, first published in the Magazine of Fantasy and Science Fiction.
Algernon unfortunately, lost his intelligence and died.[9]
The book was more than a novel, it was a prediction, and now, sixty-six years after the publication of Algernon, we are well on our scientific way of creating a lab full of potential Algernons.
Our society is cognizant of the need for the ethical treatment of animals, and of establishing laboratory standards for animal experimentation in furtherance of medical research eventually designed to benefit humans.
But, when we are on our way to humanizing animals, making them more cognizant, more intelligent, potentially more like us, there will be a need for legislation. It will need to contain protocols and procedures in genetic research so that we don’t take this country, and other countries engaged in this type of research, and turn them into Islands of Doctor Moreau.
We need mice for medicine, and they eventually may need us for legislation regarding the alteration of their bodies, minds, and perhaps even self-awareness.
We must demonstrate ethical courage in this Brave New World of human-animal hybrid creation.
Hopefully, our society and our legislators will ‘man up.’
[1] Comparative transcriptomics in human and mouse NATIONAL REVIEW OF GENETICS, Breschi, et. al. May 8, 2017 https://pmc.ncbi.nlm.nih.gov/articles/PMC6413734/
[2] Scientists made a mouse embryo that’s 4% human Kaur, 5/21/2020 CNN https://www.cnn.com/2020/05/21/us/human-mouse-chimera-hybrid-scn-trnd
[3] Scientists Put A Human "Language Gene" Into Mice Hale, 3/13/25 IFL SCIENCE https://www.iflscience.com/scientists-put-a-human-language-gene-into-mice-and-curious-things-unfolded-78418
[4] HUMAN DNA SPLICED INTO MICE CAUSED THEM TO GROW ABNORMALLY LARGE BRAINS Whalen, 5/16/25 https://thedebrief.org/human-dna-spliced-into-mice-caused-them-to-grow-abnormally-large-brains-revealing-clues-to-evolution-of-intelligence/
[5] https://www.congress.gov/bill/118th-congress/senate-bill/751
[6] https://www.govtrack.us/congress/bills/119/hr2161
[7] MISSOURI MEDICINE Bryda, 2013 https://pmc.ncbi.nlm.nih.gov/articles/PMC3987984/