Cryobiological preservation of Drosophila embryos.

The inability to cryobiologically preserve the fruit fly Drosophila melanogaster has required that fly stocks be maintained by frequent transfer of adults. This method is costly in terms of time and can lead to loss of stocks. Traditional slow freezing methods do not succeed because the embryos are highly sensitive to chilling. With the procedures described here, 68 percent of precisely staged 15-hour Oregon R (wild-type) embryos hatch after vitrification at -205 degrees C, and 40 percent of the resulting larvae develop into normal adult flies. These embryos are among the most complex organisms successfully preserved by cryobiology.