Genetic preservation provides a permanent safeguard for mouse strains through biological sample cryopreservation technology, completely avoiding various uncontrollable risks associated with live animal preservation. Two validated standardized cryopreservation options are offered:
1. Embryo Cryopreservation：Early-stage embryos (2-8 cell stage) are collected from foundation colony females, treated with cryoprotectants, subjected to programmed freezing, and stored in liquid nitrogen at -196°C. Hundreds of embryos are routinely preserved per strain. This method completely preserves the individual's entire genome, and the offspring obtained after thawing have a genetic background completely consistent with the original strain. It is the gold standard for preservation.
2. Live Animal Preservation：Maintaining continuous live breeding of the core population within a barrier facility serves as an active repository of strain resources. Its core lies in establishing a scientific and stable breeding system:
● Foundation Colony Management: Foundation colony reproduction is typically conducted through long-term co-housing at a ratio of 1 male : 2-4 females. Pedigree records and regular rotation are used to strictly control the inbreeding coefficient and maintain genetic diversity.
● Production Colony Expansion: Breeders are obtained from the foundation colony to form temporary mating pairs at a ratio of 1 male : 1-2 females for rapid expansion of offspring numbers to meet experimental or supply needs.
● Dynamic Monitoring and Replacement: The foundation colony undergoes rigorous microbiological, genetic (e.g., genotyping), and reproductive performance monitoring. Outstanding individuals are regularly selected (typically every 4-6 generations) from early offspring to replace members of the foundation colony, preventing genetic drift and fertility decline.
● Risk Control: Live animal preservation is highly dependent on the biosecurity stability of the facility environment. Risks of strain loss or degradation exist due to disease outbreaks, operational errors, accidental disasters, or genetic contamination (e.g., mismating). Therefore, it must be combined with the cryopreservation option described above to form a dual-protection strategy of "live usage + cryopreserved backup."