Why mouse genetics?

Mouse and Human share 98% of same genes

Why is so much medical research done with mice? And what does it mean when scientists talk about a mouse model?

As different as they appear, humans and mice are surprisingly similar. We share between 95 and 98 percent of our genomes and get most of the same diseases, for many of the same genetic reasons. Therefore, the results of mouse experiments often correlate to human biology.

In other words, a mouse with a specific disease or condition can serve as a model or stand-in for a human patient with that same disease or condition. This allows scientists to conduct experiments that would be ethically impossible in people. Such experiments yield insights into human biology that can lead to better diagnosis and treatment of many diseases.

The mouse is a powerful research tool in particular because of our ability to manipulate its genome directly. This provides a way to model specific human diseases when the causative gene or genes are known. For example, the manipulation of genes involved in cancer has enabled the creation of hundreds of mouse models of human cancer, greatly enhancing our ability to find effective treatments for many types of the disease.

Lenny Shultz
Leonard Shultz, Ph.D

One particular type of mouse has become an exceptional research tool. Jackson Professor Leonard D. Shultz, Ph.D., and his research team spent years engineering a “humanized” mouse, also known to colleagues as “Lenny’s mouse.”

Because its immune system has been altered, the mouse can accept a variety of human cells —blood, immune, cancer, etc. — without rejecting them, as would normally happen when “foreign” cells are introduced. This allows researchers to experiment with human cells in new ways and to translate the results much more directly to human medicine.

“This humanized mouse provides insights into living human biology that aren’t otherwise possible,” Shultz says. “The challenge was creating a mouse model with an immune system that was not so robust that it would reject human tissue and cells and not so weak that it offered the mouse insufficient protection from infection and premature death. With both a low immunity and a relatively long lifespan of more than 90 weeks, this strain allows the long-term efficacy, as well as safety, of different therapies to be determined.”

Researchers worldwide turn to The Jackson Laboratory for our eight decades of experience and know-how in experimental mouse genetics. In fact, we provide more than 7,500 strains of genetically defined mice and a wide variety of mouse services to 20,000 laboratories at 900 institutions in 56 countries around the world.

Our expertise in experimental mouse genetics is leading to better treatments for cancer, diabetes, Alzheimer’s, cardiovascular disease and many other conditions that undermine human health and longevity.

Advantages of the mouse

Mice are the most commonly used animal model for studying human disease, and for many good reasons:

  • Mice are biologically very similar to humans. We share 95 percent of the same genes, and our immune systems are even more compatible. Mice and humans get many of the same diseases, for the same genetic reasons.
  • Mice can be genetically manipulated to mimic virtually any human disease or condition. The Jackson Laboratory now maintains more than 7,000 genetically defined strains of mice.
  • Mice can be inbred to yield genetically identical strains. This uniformity allows for more accurate and repeatable experiments.
  • Mice have an accelerated lifespan, with one mouse year equaling about 30 human years. Therefore, their entire life cycle can be studied within only two or three years.
  • Mice are well understood because they have been used in biomedical research for nearly a century.  The Jackson Laboratory began using and developing mice in 1929.
  • Mice are a cost-effective and efficient research tool. They are small, they reproduce quickly, and they are relatively easy to handle and transport.