State of the art and application of gamete and reproductive tissue banking in wildlife conservation.

In this Anthropocene era, we are witnessing a rapid loss of biodiversity. To date, nearly 25% of the approximately 6,000 vertebrate species assessed by the International Union for Conservation of Nature are threatened with extinction. While the preservation of natural habitats remains crucial, the management of wildlife populations under human care has also played a critical role in the recovery of several threatened and endangered species. Because ex situ wildlife populations are often small and geographically isolated, careful and strategic genetic management is of utmost importance. The ability to store reproductive cells and tissues long-term-either in liquid nitrogen or as dry material at room temperature-is extremely valuable. It enables the infusion of genetic material into living populations, extends generation intervals, and helps preserve genetic diversity. Furthermore, these banked materials serve as a form of insurance for future species restoration programs. Consequently, efforts have been made to develop cryopreservation protocols for sperm, eggs, embryos, and gonadal tissues in wildlife species. Despite several achievements and milestones-particularly in sperm cryopreservation-significant challenges remain. In this review, we examine the status of cryopreservation protocols for gametes, embryos, and gonadal tissues across various wildlife taxa, highlighting recent successes and ongoing obstacles to advancing these efforts. Additionally, we explore emerging technologies that enhance cell survival and facilitate the integration of genome resource banking into species conservation programs.