Salmon Made to Bear Trout
Success shows sterile animals could become surrogates for extinct species
By Jonas Oransky,  Newser Staff
Posted Sep 14, 2007 6:36 PM CDT
Graphic shows surrogate broodstocking technique used to produce a rainbow trout from sterile salmon; 2c x 3 1/2 inches; 96.3 mm x 88.9 mm   (Associated Press)
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(Newser) – Cue the world’s most peculiar baby announcement: Masu salmon have produced rainbow trout offspring, with an assist from scientists that could lead to the preservation of rare fish species. Trout sperm stem cells had already been injected into salmon embryos to produce salmon with trout sperm; now the same early sperm cells have been used to produce female salmon with trout eggs, Nature reports.

Eggs can be extremely difficult to preserve; hence the importance of being able to produce viable trout eggs from sperm stem cells. Scientists also struck gold by using otherwise sterile salmon, ensuring a high success rate in the engineered breeding. The research demonstrates a remarkably high genetic flexibility among the fish—one that bodes well for their endangered relatives.