You see, when they shipped us off to colonize Mirabile, they were into redundancy. We got cold-storage banks of every conceivable species (I use the "we" loosely; I'm third-generation Mirabilan myself.) But on top of that we also got the redundancy built right into the gene helices of all the stored species. Some bright-eyed geneticist back on Earth had apparently gotten that idea just before the expedition set off: genes within genes, helices tucked away inside other helices.Of course, there were unintended consequences:
It was a good idea in theory. If we lost a species (and lost the ability to build it ourselves), sooner or later it would pop up spontaneously - all it needed was the right environmental conditions. Given the right EC, every hundredth turtle would lay an alligator egg.
In practice, it was a rotten idea. We'll never lack for alligators, not on Mirabile. They didn't tell us how to turn off those hidden helices, or if they did, the technique was only described in that part of ship's files we'd lost. So we Jasons have a running battle with cattle that are giving birth to reindeer and daffodils seeding iris (or worse - cockroaches).Yes, the biology is extremely improbable - it's hard to imagine an entire vertebrate genome silently implanted in the genome of another (implanted microbial genomes are possible, of course) - but it does raise interesting issues about genetics, embryonic development, and the environment. In fact, the HHMI BioInteractive site has several study questions based on the biology of Mirabile (scroll to the bottom of the page), which I think could be the basis of an interesting student discussion of those topics.
Meanwhile, in the manner of all genes, the hidden genes mixed. While the turtle genes were reproducing turtles, the alligator genes tucked in with the turtle genes were mixing with god-knows-what. So given the right EC, we got chimera - familiarly known as Dragon's Teeth.
I've only read the story that the quote above came from, "Kangaroo Rex", in an anthology, because, unfortunately, Mirabile is now out of print. Kagan's other works are available, however including her novel Hellspark (which has interesting aliens) and the Stark Trek tie-in Uhura's Song . On her web site you can read her short stories "Love Our Lockwood" (about an alternative history election) and "Standing in the Spirit" (a Christmas story).
Tags: Janet Kagan, Mirabile, genetic engineering