Efficient Mouse Colony Management: FAQs on JAX’s Cryopreservation, Cryorecovery, and Breeding Services
At The Jackson Laboratory (JAX), cryopreservation is a cornerstone of our research and colony management strategy. With decades of experience, we have optimized our cryopreservation protocols and established refined cryoprotectant solutions to safely preserve mice on both inbred and diverse genetic backgrounds, facilitating the reliable and long-term storage of valuable models. Cryopreservation is an invaluable tool for cost-effective colony management and forms the foundation of our ability to maintain and distribute over 11,000 genetically engineered mouse models worldwide.
Below, we answer the most frequently asked questions about JAX’s cryopreservation, cryorecovery, and breeding services—so you can leverage the same trusted methods in your research.
FAQs for Cryopreservation
Did you know The Jackson Laboratory pioneered embryo and sperm cryopreservation? JAX Cryopreservation Services enable you to not only conserve resources when you are not actively using a mouse model, but also ensure you are protected from losing your valuable strains due to natural disasters, funding cuts, facility issues, breeding issues, genetic drift, or any other unforeseen event.
Can JAX cryopreserve my strains as frozen sperm or embryos?
Yes! JAX offers both sperm and embryo cryopreservation services with short- or long-term storage options. We can also recover your strains when needed and coordinate the distribution of live mice or cryopreserved material to collaborators worldwide. We have cryopreserved tens of thousands of strains and recover thousands of strains every year, shipping mice and germplasm globally. If you have an urgent or high-volume need, we have the infrastructure and expertise to cryopreserve hundreds of strains at once, supporting institutions of all sizes.
Should I cryopreserve my mice myself or outsource the process?
While it may seem straightforward, establishing and maintaining an in-house cryopreservation program is often not cost-effective for small to mid-sized academic labs or biotech organizations. The real challenge lies not just in freezing mouse sperm or embryos—but in the infrastructure, training, and long-term support required to do it reliably.
Cryopreserving mouse germplasm requires specialized equipment, expert staff, rigorous quality control, and proper storage conditions. Even minor deviations in protocol can lead to unrecoverable samples or introduce unwanted genetic variability. For many organizations, the investment in space, equipment, and personnel needed to ensure high-quality cryopreservation and successful recovery is simply too great.
At JAX, we not only offer proven cryopreservation services using validated protocols, but we also store all samples in two geographically separate facilities—a critical safeguard against freezer failure or disaster-related loss. Many organizations have successful COREs, so even if you choose to cryopreserve in-house or use a local core, JAX can serve as a secure secondary storage site to protect your valuable strains.
If you are considering doing it yourself, we offer both a sperm cryopreservation kit and hands-on training courses to help. Samples cryopreserved using our kit can also be shipped back to JAX for safe long-term storage.
Whether you are outsourcing or going in-house, always confirm that your provider can properly handle, store, and recover your specific strains. The stakes are high—and choosing the right partner matters.
Is it best to cryopreserve sperm or embryos?
The best method depends on your strain’s genetic complexity and your research goals. In general, ask yourself two questions:
Is your strain on a standard inbred background or carrying only a single mutation?
→ Sperm cryopreservation is usually the most efficient and cost-effective option. It allows for long-term storage and easy recovery when paired with in vitro fertilization (IVF).Does your strain have a complex or unique genetic background, and/or carry multiple mutations or transgenes?
→ Embryo cryopreservation may be the better choice. It enables direct recovery of the exact genetic background and genotype combinations needed for experiments.
Both methods are effective, and JAX can help you choose the most appropriate approach based on your strain, research goals, and timeline.
What are the advantages of sperm cryopreservation?
Sperm cryopreservation is fast, cost-effective, and requires only two male mice to archive a line. One of its biggest advantages is scalability: because millions of sperm are stored per sample, you can generate large cohorts efficiently during recovery. This makes it a practical choice for labs needing rapid colony regeneration or large-scale experimental cohorts.
How many young males do I need to send for sperm cryopreservation?
We require two healthy male mice between 8 and 16 weeks of age for sperm cryopreservation. This age range ensures optimal sperm quality and recovery success. If you are unable to meet these criteria or have concerns about your strain, contact us—we're happy to discuss your specific situation.
How do I know that the sperm will be viable in the future?
It is best practice to perform quality control checks (QCs) at the time of cryopreservation. There are several quality control options. The most basic is to test the motility of thawed sperm samples. While useful, motility alone does not guarantee fertilizing capacity. Performing a small IVF trial QC provides greater confidence in future recovery. It can confirm that the sperm have retained the ability to fertilize oocytes successfully. This QC is the one most commonly used. The most rigorous QC involves performing a full cryorecovery producing live mice with genotyping, to confirm that the expected genotype is present. This is the standard QC approach JAX uses for all publicly available strains in our repository.
How many males and females do I need to send for embryo cryopreservation of my strain?
For standard embryo cryopreservation, we typically require 3-4 healthy males, 8-16 weeks of age, and 25-30 female oocyte donors. This setup is generally sufficient to produce approximately 250 cryopreserved embryos. However, outcomes can vary significantly depending on several factors unique to each strain. Multiple attempts may be required. We have cryopreserved and recovered embryos from thousands of strains and can draw on our experience to help plan your project to maximize efficiency and success.
How long does it take to cryopreserve sperm and/or embryos?
Most cryopreservation projects are completed within 12-15 weeks. For sperm cryopreservation, we store 19 straws per strain. Each straw contains four aliquots of sperm stored for future recovery. For embryos, we aim to store approximately 250 embryos per strain, distributed across 10 vials for long-term storage.
How should sperm and embryos be stored?
Sperm and embryos must be stored at ultra-low temperatures, typically in liquid nitrogen, to maintain long-term viability. Storage in an environment where thermal stability can be guaranteed is critical, as any fluctuations can compromise the genetic integrity of the material. Best practice is to store samples in multiple, geographically separated tanks to reduce the risk of total loss from equipment failure or natural disasters. At JAX, we store samples in two or more geographically separated locations. Our facilities are also equipped with redundant local and remote alarm systems, backup power infrastructure, and on-site bulk liquid nitrogen storage to safeguard germplasm under our care—24/7.
How cost effective is it to freeze down a strain?
Cryopreservation costs are typically recovered through cage-cost savings in just months. Colony costs depend on the number of boxes maintained and the cage cost/day. The cost to maintain a heterozygous colony that requires frequent genotyping ranges from a few thousand dollars to over $10,000 per year. As shown in the graph below, even in a scenario with low per diem rates, the cumulative cost of maintaining a colony increases significantly faster than the cumulative cost of cryopreserving a strain. This strategy is cost-effective even if periodic recoveries and subsequent short-term maintenance of a live colony are needed (e.g., between years 2-3 and 6-7, as illustrated).
FAQs for Cryorecovery
Cryopreserving lines enable rapid cryorecovery of strains on demand, minimizing vivarium costs and helping scale rapidly and efficiently for:
Collaborations
Reinitiation of projects
Reevaluation of data
Fulfilling the NIH mandate to share new model organisms with the research community
Can JAX recover my strain from frozen sperm or frozen embryos?
Yes. JAX successfully recovers over 2,500 strains each year for academic, biotech, and pharmaceutical researchers worldwide. We can recover your cryopreserved strains for your next project re-initiation, for your collaborators, or cryorecover strains from your collaborators’ cryopreserved stocks.
How long does it take to recover a frozen strain?
Most strain recoveries are completed within 12 to 15 weeks. Timelines may vary slightly depending on your specific project needs.
What is more expensive: maintaining a strain I might not use within the next six months, or cryorecovering it later when needed?
In most cases, maintaining a live colony of an unused strain is significantly more expensive than cryopreserving it and recovering it later. Cryopreservation costs are typically offset by cage-cost savings just within a few months (see the cost comparison graph above). JAX has helped hundreds of institutions reduce operational expenses by archiving mouse lines they do not need immediately, while ensuring fast recovery when they are needed again. Many researchers choose to cryopreserve strains proactively, freeing up vivarium space and budget for active studies, without sacrificing future access to critical models.
What is the health status of mice cryorecovered at JAX?
Mice recovered from frozen sperm or embryos at JAX are specified and opportunistic pathogen-free (SOPF) and meet our highest health status.
FAQs for Breeding
JAX provides custom breeding solutions to maintain, expand, and ship your mouse lines—anywhere in the world, exactly how and when you need them.
Why are my mice not breeding?
Many factors influence mouse breeding success: health status, handling, diet, and the number of hours of light and darkness. It is vital to ensure that they have an adequate dark period for them to mate. Additionally, some genetically modified strains or disease models naturally exhibit reduced fertility or poor reproductive performance. For more information, check out some tips on general husbandry.
What are the advantages of maintaining mouse colonies at JAX?
JAX offers end-to-end colony management using a data-backed framework to save you time and reduce costs.
Experience: No one has more experience managing mouse colonies. Our Breeding Services team combines expertise in genetics, veterinary pathology, colony design, and project management to support even the most complex models.
Cost-effective: If you are limited on time, space, or technical staff, outsourcing colony maintenance and breeding to JAX helps conserve vivarium space and technician hours. We handle breeding, genotyping, record-keeping, and shipping, so you can focus on your research. And with JAXConnect™, you stay fully informed and in control, with real-time visibility into your colonies at every stage.
Maximal health status: At JAX, your colonies are maintained in economical barrier cage housing and are maintained SOPF, eliminating the need for quarantine.
Rapid Colony expansion: Jumpstart your timelines by 3-6 months with IVF-assisted rederivation and colony expansion.
You can access a continuum of integrated services, including blood and tissue collection, genotyping, surgery, histopathology, gene expression, phenotyping, and a suite of in vivo pharmacology services.
What types of breeding projects can JAX support?
JAX supports custom breeding projects of all sizes and complexities – whether using your mice or JAX® Mice. Our team can manage everything from routine colony maintenance to advanced, multi-generational crosses. We can also maintain mice on special diets, rapidly backcross strains to a new genetic background, and efficiently scale for ongoing production of study cohorts for downstream experiments. If you do not see the service you need listed here, reach out to our team, we are happy to discuss customized solutions.
Where can I find breeding schemes used to maintain JAX strains?
To view the breeding scheme for a specific strain, go to its strain datasheet using the stock number. Then navigate to the “Technical Support” tab, where you will find the mating system used at JAX and important breeding considerations for that strain. Please note that mating schemes are displayed as the Female genotype(s) x Male genotype. Keep in mind that the breeding scheme JAX uses may not be the one you need to produce a specific genotype for your studies.
What is the price for breeding mice at JAX?
The cost depends on several factors, including the strains you plan to breed (whether live or cryopreserved, and their breeding performance), the number of mice needed, their genotypes, ages, and sexes, as well as the number and frequency of shipments required for your project. Because each project is unique, we recommend contacting our team for a personalized quote tailored to your specific breeding and shipment needs.
How long will it take to generate my experimental model developed by breeding two or more strains together?
The timeline depends on several of the same factors outlined above. We recommend contacting our team to discuss your specific model and receive an estimated timeline tailored to your needs.
How do I figure out what breeding schemes to use to generate strains with multiple mutations?
When designing a breeding strategy, focus on the genotype needed, rather than the phenotype wanted. This approach allows you to plan each breeding step more effectively and calculate the expected Mendelian ratios, so you can ensure you have enough mice for subsequent rounds of breeding or sufficient mice for your experiments. Specific mating schemes will depend on the genotypes required for the experimental and control mice needed, and the viability and fecundity of homozygous mice (watch this JAX On-Demand webinar for more information).
If your question was not answered in this FAQ or you would like more information about anything mentioned above, please reach out to micetech@jax.org. We are happy to help you find the colony management solutions that best support your research.
Explore JAX’s comprehensive colony management services and resources.
References
Byers SL, Payson SJ, Taft RA, (2006). “Performance of ten inbred mouse strains following assisted reproductive technologies (ARTs). “ Theriogenology. 65(9):1716-26. PMID: 16271754
Kopeika J, Thornhill A, Khalaf Y, (2014). “The effect of cryopreservation on the genome of gametes and embryos: principles of cryobiology and critical appraisal of the evidence.” Hum Reprod Update. Dec 17. pii: dmu063. [Epub ahead of print] PMID: 25519143
Ostermeier GC, Wiles MV, Farley JS, Taft RA, (2008). “Conserving, Distributing and Managing Genetically Modified Mouse Lines by Sperm Cryopreservation“. PLoS ONE 3(7): e2792. doi:10.1371/journal.pone.0002792. PMID: 18665210
Wiles MV, Taft RA, (2010). “The sophisticated mouse: protecting a precious reagent.” Methods Mol Biol. 602:23-36. doi: 10.1007/978-1-60761-058-8_2. PMID: 20012390