Mirabile by Janet Kagan

I’d expected, just a few twists off normal red kangaroo.
    “Roo stew?” said a voice behind me.
    “Sure,” I said, without looking up, “still perfectly edible, despite those.” I tapped the offending genes on the monitor.
    “Janzen,” said Leo’s voice, “No point talking to her when she’s reading genes.
    She’s not talking about the same thing you are.”
    That was enough to make me turn away from the screen. I looked at Janzen.
    “Sorry,” I said, “What was it you wanted to know?”
    “I just asked if you’d mind having roo stew for dinner. I intend to eat a lot of roo while I still have the option.”
    “Say yes, Annie.” That was Leo again. “Janzen and Moustafa make the best roo stew I’ve ever had. Even Chris couldn’t beat their recipe.”
    “That’s some recommendation! Can I get in on this?” That was Susan. “I put the sheep samples in the truck, Mama Jason; all set for in vitro in case we need them. Is that your rex breeder?
    Sangster won’t talk about what you guys found. What did you do to her? Threaten her with a corn crop that sprouts cockroaches?”
    “One thing at a time,” I said. “Janzen, yes, thank you. I’m extremely fond of roo myself. Will there be enough for Susan too, or shall I make her eat rations?”
    Susan threatened to punch me. Janzen grinned at her and said, “Plenty enough, Susan. Now I know why Leo wants to hook up with Annie. Just his type.”
    To change the subject, I tapped the monitor again and said, “That’s our most likely candidate for rex breeder. I was just about to check for secondary helices.
    You can watch over my shoulder, unless you want to watch how Janzen and Moustafa make stew. The recipe’d make a good birthday present for Chris…?”
    Susan looked horribly torn for a brief moment. Janzen grinned at her again and said, “I’ll write out our recipe for you, Susan. You stick here and tell me what I need to know about the kangaroo rexes.” The kid had a lot in common with his granddad.
    While Susan pulled up a chair, I turned back to the monitor and started reading genes again.
    Yup, there was a secondary helix, all right. I split the screen, called up the gene-read on my kangaroo rex, and compared the two. No doubt about it.
    “Thanks for saving old Striped Rump, Leo. She’s it.”
    I stored that to send back to the lab and called up the next sample. “Let’s see how many other rex breeders we’ve got.”
    By the time Moustafa dished out the roo stew, I’d found two more rex breeders in the sample of thirteen. And they were all remarkably consistent about it. “Hell,” said Leo.
    “Not exactly, Noisy,” Susan said. “That means most likely the kangaroo rex is an intermediate for an Earth-authentic.”
    I was momentarily more interested in the stew than in anything else. It lived up to Page 39

    Leo’s billing. I was still trying to place the spices Janzen and Moustafa used when Leo laid a hand on my arm to get my attention. “Mmmph?” I said, through a mouthful.
    “You’ve got to train your assistants to use less jargon,” he said.
    I scooped up another forkful of stew and simply eyed Susan.
    “Ooops,” she said. “Sorry, Noisy. A true Dragon’s Tooth is usually a chimera—bits and pieces of the genetic material of two very different species. Even a plant-animal combination’s possible.
    But it’s not consistent.
    “If we’ve got three roos that are going to at some time produce rexes, all of which are close enough genetically to interbreed, then most likely it’s not a Dragon’s Tooth. Most likely it’s the first visible step on the chain up to another Earth-authentic.” She waited anxiously to see if he’d gotten it this time. When he nodded, she dived back into her own dinner. “Great stew, Moustafa, Janzen. I’d sure hate it if we have to kill off the roos.”
    “Any idea just how big the roo population is?” I asked the two local kids.
    They exchanged a glance. Moustafa said, “Couple