Wednesday, January 02, 2008

Transgenics for Trout?

A new science column in the New York Times reports on experiments that use one species of fish to breed another.

[R]esearchers have done a series of transplantation experiments on rainbow trout (Oncorhynchus mykiss) and masu salmon (Oncorhynchus masou) — a pair of species that began to diverge at least 8 million years ago. Their most recent and surprising result is that spermatogonia from rainbow trout will, if injected into the body cavity of a salmon embryo, migrate to the gonads of the developing salmon and colonize them. What’s more, if the salmon is female, the spermatogonia will turn into eggs....

But although the transplanted trout cells obey the instructions they get from the salmon body they’ve moved into, and (usually) become incorporated into that body, the genes inside them are still trout genes. Which means that when the salmon spawned, they produced trout fry.

The lead researcher in this study hopes that the technique can be used to sustain numbers of popular food fish threatened with overfishing. A noble goal, surely, but in my mind, this research inspires fantasies of recruiting abundant populations of rough fish in marginal trout streams to produce more trout. Technologies developed for the most practical ends often do find recreational uses.

Seriously, though, the really interesting part of this is the capacity of the gamete-producing cells to switch gender depending on the constitution of the embryo in which they're implanted. One more case of how our most rock-solid realities prove to be matters of circumstance. Some people find that notion unsettling, though anglers ought to be comfortable enough with it, since in the pursuit of fish, chance, contingency, and randomness are matters of course.

2 comments:

The Trout Underground said...

The downside here is how agencies might use non-endangered species (who might be less picky about habitat) to reproduce endangered species who are picky about where they reproduce, thereby avoiding the critical habitat issues in the first place.

That's more a hatchery fix than a real one, and I hope like hell that doesn't become a reality.

Shupac said...

I'm not too serious here, though the science is very interesting. I expect the cost of this would be prohibitive for non-commericial ventures.