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Transgenic Mice Are Poor Models for Human Disease
More than one hundred million mice and rats are estimated to be used in medical experiments each year in the United States. Much of this research is funded by the National Institutes of Health, which spends billions of dollars on transgenic mice and other genetically modified animals.
What are transgenic mice?
Recently, there’s been buzz about transgenic mice, leaving many wondering what "transgenic” even means. Transgenic mice are a kind of genetically modified mice that have their genetic material, or DNA, modified in the laboratory as embryos. New DNA can be inserted, or sections of DNA changed or removed, in an effort to learn about the function of genes or to attempt to model human diseases. While some scientists hail these mice as revolutionary for medical research, genetically modified mice are, in fact, extremely poor models for human disease.
The process of creating genetically modified mice is extremely inefficient, with many mice dying before or around the time of birth. Often, mice with the intended modifications also have unwanted genetic changes, which cause suffering and death or which render those mice unsuitable for research. In addition to these off-target genetic alterations, species-specific differences—including size, lifespan, anatomy, physiology, genetic background, and differences in how genes work—render processes such as drug metabolism and immune function impossible to reliably replicate, seriously limiting the ability of genetically modified mice to accurately model human biology and diseases.
Despite these significant problems, genetically modified mice continue to be used to study many diseases, like cancer and Alzheimer’s disease, but these fail to translate to human benefit. In cancer research, differences in metastasis rates and an inability to reliably model sporadic tumor growth make them unable to replicate important human cancer characteristics and drug responses. In neurodegenerative disease research, genetically modified mice are commonly used but time and again fail to accurately model human disease complexity, pathology, symptomology, and trajectory.
What can scientists use instead of transgenic mice?
Human-specific nonanimal methods like organoids, tissue chips, 3D bioprinting, digital twins, and artificial intelligence are effective approaches for medical research and testing. These methods use human cells, tissues, and data to model human biology and disease more accurately than animals and improve drug development.
Human-specific methods can be derived directly from patients to include important patient-specific genetic backgrounds and disease pathology. In this way, they can be used to promote health equity and precision medicine in ways that are impossible to do using animals. Human-specific methods can also be derived from genetically modified human cells to reliably create a wide variety of otherwise inaccessible human tissue types for effective disease modeling. And clinical studies, including advanced imaging, genetic analysis, and noninvasive clinical trials use voluntary human subjects to better understand, diagnose, and treat diseases.
These innovative approaches are available for researchers to use in many applications instead of transgenic mice and other animals. To learn more about them, check out our New Approach Methodologies infographic and be sure to subscribe to the Physicians Committee’s Innovative Science News.
