Researchers routinely use model organisms in their work to understand biological processes and diseases. Experimental work with animals dates to ancient Greece [1], and many of the key breakthroughs in biology research and medicine were made using model organisms. Common model organisms include laboratory workhorses like the mouse (Mus musculus), the rat (Rattus norvegicus), the fruit fly (Drosophila melanogaster), the nematode (Caenorhabditis elegans), the zebrafish (Danio rerio), brewer’s yeast (Saccharomyces cerevisiae), and the bacteria (Escherichia coli).
Interestingly, many of our favorite farm animals, or livestock species, are also model organisms, including the horse (Equus caballus), cattle (Bos taurus), chicken (Gallus gallus), pig (Sus scrofa), sheep (Ovis aries), and goat (Capra hircus).
In this blog, we would like to focus only on rodent model organisms. Mouse and rat are two of the most common rodent model organisms used worldwide. Some lesser-known rodent model organisms include the Chinese hamster (Cricetulus griseus), Guinea pig (Cavia porcellus), and the naked mole-rat (Heterocephalus glaber).
We’re not here to simply list common model organisms. Let’s discuss how researchers use the rodent species mentioned above. Both mouse and rat are used to study the complex physiological processes present in humans, such as immune, endocrine, digestive, nervous, and cardiovascular systems. Rats are particularly good model organisms for central nervous systems process, as the rat brain is structured similarly to the human brain. Mice and rats also suffer from diseases to these systems, and thus they are used to study cancer, diabetes, and Alzheimer’s disease among many other ailments. Chinese hamsters are famous for their ovarian cells. Chinese hamster ovary cells, or CHO cells, are commonly used for the mass production of recombinant proteins. Guinea pigs have waned in popularity as a model organism in the last 50 years, as researchers favor mouse and rat due to their better defined genetics. Guinea pigs remain solid model organisms for the study of reproduction, diabetes, and infectious diseases.
The newest addition to the rodent model organism family is the naked mole-rat. These burrowing rodents are native to Eastern Africa and possess some truly remarkable characteristics noted below:
- They form eusocial colonies similar to ants and bees, which is very rare in mammals.
- They are essentially cold-blooded in how they regulate their internal temperature-another quality that is extremely rare in mammals.
- They rarely get cancer.
- They are resistant to some types of pain.
- They can survive up to 18 minutes without oxygen.
- They can live for 30 years, which significantly exceeds the life expectancy for a rodent species of their size.
One of the huge advantages of studying model organisms is the increased availability of research tools over non-model organisms. For example, a researcher studying a rare species of spider would have immense difficulty designing qPCR assays. Not only would they need to generate transcriptome-sequencing data, but also they would need to design and optimize the primers and probes. For model organisms, researchers can acquire publicly available sequence data, and design/optimize their own qPCR assays. Alternatively, they can save time by utilizing Applied Biosystems™ TaqMan® Gene Expression Assays, which are available for the five rodent model organisms we’ve been discussing:
| Species | No. of assays |
| Mouse | 177,667 |
| Rat | 147,471 |
| Naked mole-rat | 149,948 |
| Chinese hamster | 154,743 |
| Guinea pig | 2,108 |
TaqMan Gene Expression Assays are also available for 23 other species, including all of the model organisms mentioned above (farm animals too), and commonly targeted microbial pathogens. Predesigned TaqMan Gene Expression Assays are skillfully designed by our expert bioinformatics team using a validated pipeline. The fluorescent Applied Biosystems™ TaqMan® MGB probe works with the forward and reverse primers to achieve gold-standard specificity and sensitivity, with assay efficiencies up to 100 ±10%. Furthermore, researchers that want to duplex their gene-of-interest with their endogenous control can easily order VIC-labeled versions of all predesigned assays.
To search for a TaqMan Gene Expression assay, start by using our new search tool
1) Replace the asterisk with the gene symbol for your gene-of-interest.
2) Choose your species from the “Species” dropdown menu.
Let’s look at the search result example below for more information on choosing and/or ordering a TaqMan Gene Expression Assay:
1) Click on “View Details” to see all of the key information about the assay (Assay Design, Entrez Gene ID, Gene Name, Gene Aliases, Chromosome Location, and NCBI RefSeq with assay location data).
2) Use the “Dye” dropdown menu to choose between FAM, VIC, and VIC-primer-limited dye.
3) Use the “Size” dropdown menu to choose between Extra Small, Small, Medium, and Large.
Find more information here:
- We have some great information, tips and educational resources in our Gene Expression Learning Center
- If you’re having any problems with your experiments, you can visit our dedicated Gene Expression Support Center
- Learn more about how we stand behind our assays with the TaqMan Guarantee.
References
[1] Cohen BJ, Loew FM. (1984) Laboratory Animal Medicine: Historical Perspectives in Laboratory Animal Medicine Academic Press, Inc: Orlando, FL, USA; Fox JG, Cohen BJ, Loew FM (eds)
For Research Use Only. Not for use in diagnostic procedures. TaqMan is a registered trademark of Roche Molecular Systems, Inc., used under permission and license.
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