Jo inserted the poop sample into the DNA sequencer, closed the lid, and tapped VACUUM START.
There was an old fashioned thrupping sound as the pump did its work. After a minute a green LED lit. Jo tapped SEQUENCE START.
A solenoid clicked as the sequencer punctured the sample capsule.
“How long will this take?” Frances asked.
“A few hours for PCR and primary sequencing, plus or minus. I wish I could give you a better estimate. Of course, if I could, it’d be because I already knew what’s in there.”
“What is in there?”
“Our little pooper is obviously a strict herbivore. We’ll have to wade through a bunch of different plant DNA, which will be a clue to diet. By far the most plentiful DNA is going to be from gut bacteria. That’s useful on its own: gut fauna are species specific. Somewhere in there will be the real prize. Little Pooper’s own DNA sequence.
“And then we’ll know what species they are?”, asked the veteranarian.
Jo Stapledon nodded. “Smoking gun. I’ve made some educated guesses, with input from a few trusted students.” Jo took a breath. “’Wallaby’ is something less than a strictly scientific term, so let’s call Little Pooper a ‘macropod’, literally ‘big foot’.
“There’s around 70 known living species of macropod altogether – the wallaby and their kin: kangaroo, wallaroo, and allies. Some of them are easily ruled out based on what we saw on camera, but I’ll come to that in a minute. Of 70-odd macropod species, about three fifths of them are registered online in GenomeEarth, either in fully or partially sequenced form. I have a post-doc at Pavlovsk Station making discreet inquiries. We want to see if other species might already have been sequenced, but not published.
Frances snorted. “Rosalind Franklin’s desk drawer?”
Jo assumed a speaker’s posture. “Rosalind Franklin’s face is tattooed on the arms of the people I’m talking about. Each sample comes with the digital signature of every technician and every reseaercher who worked on it. Academic priority is sacrosanct in this community. It’s chain-of-custody rules, too, frankly, since DNA evidence has had legal significance for over a century. We will not be stealing data, just asking for preprints.”
Frances sat back and mouthed okay. Jo let the moment sit, then continued.
“If Little Pooper was a research specimen, we’ll probably get lucky on species ID. There are a relatively limited number of wallaby species favored in captive research, and all of them were fully sequenced long ago. On the other hand, if it’s a case of a loose exotic pet, it might be a more obscure breed.
A shadow crossed Frances’ face. “I could do with a lot fewer ‘exotic pet owners’ in this world. If these babies escaped from one, it’s irresponsible stewardship. And if they were dumped…. I don’t even want to imagine.”
Jo nodded. “Same in my hemisphere. You said you’re sure that there’s more than one of them, and I’m finding myself in agreement. They might not even be all the same species. I wish I had a daylight photo. What more site context can you give me?”
“I documented eleven sites, over two weekends,” replied the veterinarian, “all in the same ten hectare plot. Seven sites were used more than once, five of them two weeks in a row. Whether by more than one individual, at any given site, I couldn’t say. It’s all GPS’ed and timestamped, in the poop ‘fridge.” Frances jabbed a thumb towards the white box whirring quietly in the corner, adorned with a “Go Aggies!” refrigerator magnet. “The ones labeled in brown ink have been through freeze-dry for moisture analysis.”
Jo joined the genome sequencer onto the ranch’s wifi network, entered ‘macropod’ into the GenomeEarth database search window, and ticked “download all” on the results.
“What’s the local fauna like? What lives in south Texas?”
“Well, I’ve mentioned deer and hare. Then there’s alligator – now that I think of it, I should give you our visitor safety briefing, but the short version is to watch out for snakes and alligators. Plenty of other reptiles. Wild pigs, bats, marmots, birds. We’re living at one of the classic crossroads of evolutionary migration here.”
Jo nodded. “You did well in focusing on hare and deer. The wallabies are both, in their native lands.”
Frances said, quickly, “You mean convergent evolution.”
“Yes. In Australia there’s places you could mistake for South Texas. Same terrain and weather, similar plant life. Nature reinvents solutions under similar conditions of life. Kangaroo are our deer – browsers.”
“And we’ve got groundhogs where you have wombats.” Frances stretched. “I could use a nap. Let your analyzer do its thing. In the morning I’ll call out to A&M, see if I can get a couple of starry-eyed undergrads out here to capsule up a few hundred more poop samples for your magic machine. Do you need to stay up all night and nurse your baby?”
“Not since my thesis days. I’ll catch you in the morning. Please ask the Wake-Up Fairy not to knock too early.”