Recent Advances in Cryopreservation of Animal Genetic Resources: Principles, Influencing Factors, and Material-Specific Challenges

Abstract

Simple Summary Freezing animal cells and tissues used for reproduction and genetic resource conservation makes it possible to store valuable biological material for future breeding, research, and the protection of endangered species. However, freezing and warming can damage cells by forming ice, disturbing their water balance, and triggering harmful oxidative stress, osmotic imbalance, and membrane damage. This review explains why these injuries occur and why different species and biological materials respond differently to preservation. It brings together evidence on sperm, eggs, embryos, stem cells, cells that give rise to sperm or eggs, reproductive tissues, and selected whole-organ models. The available evidence shows that no single freezing method or protective solution is best for every material. Survival after warming does not necessarily mean that a sample can perform its intended biological function, such as fertilizing an egg, producing healthy offspring, or restoring tissue or organ function. New methods that control ice formation, deliver protective solutions more gently, or warm samples more evenly are promising, but many still require further safety testing and confirmation across laboratories. Matching preservation methods to each species and material will improve animal breeding, genetic resource banking, and wildlife conservation.