Female Germ Cell Biobanking for Conservation of Endangered Avian Species

抄録

　The preservation of germplasm has become key to conserving genetic resources and safeguarding species diversity. In avian species, the rapid decline of biodiversity necessitates the development of comprehensive genetic resource preservation strategies. While semen cryopreservation is widely used, it fails to capture maternally inherited genetic components, such as mitochondrial DNA and the female-specific W chromosome. Thus, developing a system for preserving female germplasm is essential. Avian embryos and oocytes are extremely difficult to cryopreserve due to their large yolk and complex structure. To overcome these biological constraints, two innovative approaches for female germline preservation have emerged: the utilization of primordial germ cells (PGCs) and ovarian tissue cryopreservation. This review summarizes current advancements in both methodologies, while comparing their technical maturity, scalability and practical applicability. PGC-based technologies, combined with germline chimera production, offer high scalability through in vitro expansion but remain constrained by the requirement for viable embryos. Conversely, ovarian tissue preservation, followed by orthotopic transplantation, provides unparalleled flexibility for field conservation, enabling the recovery of genetic material from post-mortem individuals. Finally, we propose a dual-track strategy that prioritizes the integration of ovarian tissue preservation to ensure that the maternal genetic contribution of every lost individual could be captured and potentially restored under appropriate conditions.