The rainbow trout researchers had no trout, but salmon as a parent. Image: Engbretson, Eric / US Fish and Wildlife Service,
Read aloud Japanese researchers have managed to give salmon couples healthy rainbow trout. In their genetic engineering approach, the scientists inject spermatic stem cells of the trout species into embryos of sterile salmon. The latter then produced sperm or eggs with the genetic makeup of the trout as they grew up. The researchers around Tomoyuki Okutsu from the University of Tokyo hope to save their endangered fish species with their technology. For their experiments, the scientists used the spermatogonia of rainbow trout. Spermatogonia refers to sperm cells in an early stage of development that still have stem cell properties. They injected them into sterile Masulach embryos (Oncorhynchus masou), closely related to the rainbow trout. Thus, germ cells with the genetic makeup of trout and the offspring of these animals was thus one hundred percent trout. These fish were also fertile and capable of producing healthy offspring.

Upon injection of spermatogonia into male embryos, they were expected to produce sperm. In contrast, when the early sperm cells were injected into female embryos, they produced functioning oocytes. Thus, both types of germ cells can be produced from this early form of sperm.

A major benefit of this technique could be in its application for the storage of genetic material of endangered fish species, as spermatogonia can be well frozen. In contrast, fish eggs are very difficult to preserve because of their size and high fat content. This has made it difficult to create a gene database for fish that contains both sperm and egg for artificial insemination.

Nature, Online Service, DOI: 10.1038 / news070910-11 Original work by the researchers: Tomoyuki Okutsu (University of Tokyo) et al .: Science, Volume 317, page 1517 ddp / Tobias Becker advertisement


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