A new technique for long-term conservation of fruit fly populations

The fruit fly Drosophila melanogaster has long been an important experimental model for biological research. While you may strive to rid your kitchen of this unwanted pest, researchers in Japan have come up with a new technique to keep Drosophila in the laboratory even longer.

In a new study published in Communications Biology, researchers at the University of Tsukuba identify a method of preserving Drosophila primordial germ cells (PGCs), which breed reproductive cells and can be used to produce Drosophila offspring when they are in implanted in a host.

Drosophila are useful as a scientific model because their genome can be easily manipulated and such genetic changes can help us understand how certain genes work. However, when Drosophila populations are sustained for extended periods of time by live cultures, unwanted genetic mutations can be inadvertently introduced into the genome. Previously, Drosophila strains have been preserved by freezing embryos or eggs, but these processes can be labor-intensive and difficult to reproduce. Therefore, the researchers looked for a new technique for preserving Drosophila strains that is simple and reproducible.

We treated PGCs from donor flies with a cryopreservative and stored them in liquid nitrogen, which keeps the samples at an extremely low temperature. We found that cryopreserved PGCs thawed and transplanted into host flies were able to produce offspring with the same genetic characteristics as the donor flies. “

Professor Satoru Kobayashi, lead author of the study

The researchers tested this technique with frozen PGCs from several Drosophila strains with different genetic backgrounds and found that frozen PGCs could effectively produce offspring regardless of the strain. The cryopreserved PGCs were still effective even after long-term storage of up to 400 days.

The researchers also transplanted frozen PGCs into a strain of Drosophila, which is normally unable to reproduce, and found that the frozen cells were able to produce offspring from these hosts.

“We are very satisfied with the results, and in fact our protocol has already been implemented in the KYOTO Stock Center of the Kyoto Institute of Technology (KIT),” says Professor Toshiyuki Takano-Shimizu at KIT. “We hope that this technique can be widely used for the conservation of Drosophila strains.”

The researchers are currently preparing a video report demonstrating their protocol to share this technique with other research teams. This method is a simple and effective way to preserve Drosophila populations for future use and to minimize the risk of unwanted genetic mutations.


Journal reference:

Asaoka, M., et al. (2021) Offspring production from cryopreserved primordial germ cells in Drosophila. Communication biology. doi.org/10.1038/s42003-021-02692-z.

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