Poultry genetic resource conservation using primordial germ cells

The majority of poultry genetic resources are maintained in situ in living populations. However, in situ conservation of poultry genetic resources always carries the risk of loss owing to pathogen outbreaks, genetic problems, breeding cessation, or natural disasters. Cryobanking of germplasm in birds has been limited to the use of semen, preventing conservation of the W chromosome and mitochondrial DNA. A further challenge is posed by the structure of avian eggs, which restricts the cryopreservation of ova and fertilized embryos, a technique widely used for mammalian species. By using a unique biological property and accessibility of avian primordial germ cells (PGCs), precursor cells for gametes, which temporally circulate in the vasculature during early development, an avian PGC transplantation technique has been established. To date, several techniques for PGC manipulation including purification, cryopreservation, depletion, and long-term culture have been developed in chickens. PGC transplantation combined with recent advanced PGC manipulation techniques have enabled ex situ conservation of poultry genetic resources in their complete form. Here, the updated technologies for avian PGC manipulation are introduced, and then the concept of a poultry PGC-bank is proposed by considering the biological properties of avian PGCs.