Offspring production from cryopreserved primordial germ cells in Drosophila

Asaoka, Sakamaki, Fukumoto et al. present a more viable method of long-term storage of Drosophila fly strains by cryopreservation of primordial germ cells (PGCs) without any drop in viability. The authors show that PGCs from stage 5 embryos can be transplanted into embryos and properly developed into germline stem cells to produce offspring of both sexes after being revived from storage in liquid nitrogen. There is an urgent need to cryopreserve Drosophila stocks that have been maintained as living cultures for a long time. Long-term culture increases the risk of accidental loss and of unwanted genetic alteration. Here, we report that cryopreserved primordial germ cells (PGCs) can produce F1 progeny when transplanted into hosts. The cryopreserved donor PGCs could form germline stem cells in host gonads and contributed to continuous offspring production. Furthermore, the ability to produce offspring did not appear to vary with either differences between donor strains or cryopreservation duration. Therefore, we propose that our cryopreservation method is feasible for long-term storage of various Drosophila strains. These results underscore the potential usefulness of our cryopreservation method for backing up living stocks to avoid either accidental loss or genetic alteration.