Lateral Transfers

The whitecap’s skin glows with a golden tan of cultured xanthophylls.  Joel’s smile grows a little more brittle.  He’s heard all about the benefits, of course. UV protection, higher blood oxygen, more energy — they say it even cuts down on your food requirements, not that any of these people have to worry about grocery money.  Still, it’s too bloody freakish for Joel’s tastes.  Implants should be made out of meat, or at least plastic.  If people were meant to photosynthesize they’d have leaves.

I wrote that back in the late nineties. I didn’t invent it. I wasn’t even the first SF writer to exploit the idea, not by a long shot. Way back in the seventies Poul Anderson’s Fire Time described aliens with photosynthetic manes — (They nibbled on them sometimes, if I’m remembering correctly. Kind of an autophagous salad bar) — and out in the real world corals and tridacnas (tridacnae?) figured out the whole symbiotic-algae thing a few million years before Starfish came out. And yet, those guys aren’t really photosynthetic; they just loan out their flesh to things that are, skim a little growth energy in lieu of rent. Some nudibranchs eat the algae outright, incorporating the still-functional chloroplasts into their tissues — but even those guys are just living off someone else’s body parts, not growing their own. Except for science-fictional creations like my filthy-rich retirees in Starfish, anyone looking for a truly photosynthetic animal was SOL.

Until now. Until these nifty little creatures showed up in Nature last week.

Photosynthetic. Aphids.

Photo from Valmallette et al.

Okay, maybe not exactly photosynthetic. It has yet to be definitively established that these little critters suck in CO­2 and exhale oxygen, so technically we could be talking about a different process. But aphids do carry the genes to make carotenoids, a photosynthetic pigment common in various algae. Valmallette et al did observe the pigment itself, distributed in a layer just below the cuticle (just about where you’d want to be if you were a solar battery, for instance). And they found that aphids kept in lit environs had higher rates of ATP production than those kept in the dark.

Valmallette et al conclude that these findings “argue for a role of chromophores as part of an archaic photosynthetic mechanism in insects”; they drop seductive hints about “an archaic photosynthetic system consisting of photo-emitted electrons that are in fine funnelled into the mitochondrial reducing power in order to synthesize ATP molecules.”

So, not symbionts. Not devoured body parts. Photosynthetic animals. How cool is that?

It’s cool enough that Valmallette et al put the word “amazingly” into the official abstract, which breaks the cardinal rule of Thall Shalt Not Inject Emotion Into Science. In this case, though, Nature apparently thought the cause was more than sufficient.

It’s unlikely that aphids evolved these genes independently. More likely the traits were acquired via lateral transfer, probably from blue-green algae. Which segues nicely into another item involving those same elements: namely, the gengineering of blue-green algae for the production of biogasoline. Apparently1 the latest issue of BioScience contains a cautionary paper on the subject by Allison Snow & Val Smith, warning against unforeseen consequences — specifically, the possibility that “transgenes … could be transferred to other species in a way that could upset a fragile ecosystem”.

As chance would have it, I recently wrote a story on this very topic for MIT Technology Review. You may remember an excerpt (to which I’m not linking because it was a rough draft, and has since been improved), which describes exactly the kind of unforeseen consequences that Snow & Smith warn us about. (Well, maybe not exactly, but then again that’s the whole thing about unforeseen consequences.) (Late-breaking update — having since seen a copy of the paper itself, let me quote a line from the abstract: “Cyanobacteria are especially difficult to evaluate because of the chance of horizontal gene transfer with unrelated microbes.” So, at least semi-exactly.) Immediate consequences, though, give rise to longer-term ones— and as Frederick Pohl famously remarked, it’s not enough to predict the automobile. Science fiction’s job is to predict the traffic jam that comes after. So I’m going to sing you out with another fiblet, in which said traffic jam is caused by a goat in the road:

…the Polish alcohol-industrial complex had, by all accounts, experienced an unexpected renaissance of late. It was impossible to regulate. The EU had tried, with their ever-widening definitions of “toxic waste”. Exorbitant licensing fees made it all but impossible to purchase the product even in the restaurants and hotels of Poland itself— and yet it persisted, wound inextricably through the very DNA of the culture. Meaderies plied a hundred types of hooch on rickety tables in town squares; unmarked crates crossed national boundaries in search of more-forgiving environmental standards; homemade stills bubbled and dripped in every basement. Alcohol even played a prominent role in Polish justice; a traditional form of capital punishment back in Medieval times had involved forcing wine down the condemned’s throat through a tube until his guts exploded. (Some whispered that the practice persisted even now, in the remote woodlands of Lubelskie.)

Over the past couple of years the win and the wódka kawa had been making inroads into North America, and its devastating effects were showing up in the most graphic PSAs the Bureau could muster. It hooked those you’d least expect, they said: real family-values types who’d never touch a chemical that hadn’t come from a pharmacy or a tobacconist. Then one day you’d find their feet, still clad in socks and shoes like a couple of smoldering galoshes on the living room carpet. Maybe a bit of carbonized tibia poking through those cauterized stumps. After the funeral you’d go downstairs to pack up their tools for Goodwill and there you’d find it, back behind the water heater where no one would ever think to look: the box with the bottles inside, still half full of that mysterious pink liquid, viscous as machine oil. The labels with the funny accents over the Cs and the strange little slashes through the Ls and all those words ending in ski. And you would curse the vile Poles and their vile killer moonshine, and you would rage at the injustice of bad things happening to good people, and words like plasmid and lateral transfer would never even cross your mind…


1I will have to take this on faith, however, since BioScience is behind a paywall and it’ll be a while before I dig out a new tunnel through such things.

This entry was written by Peter Watts , posted on Wednesday August 22 2012at 11:08 am , filed under biology, biotech, evolution, fiblet . Bookmark the permalink . Post a comment below or leave a trackback: Trackback URL.

20 Responses to “Lateral Transfers”

  1. “Photosynthetic animals. How cool is that?”

    That is quite fucking cool. Quite fucking cool indeed.

    Now when can I get the genes for it installed?

  2. 1) Another book which explored this idea, which I read as a wee thing; Top Secret, by either James Reynolds Gardiner or James Reynolds (listed differently in different editions), Amazon page has pic of the cover I remember.

    http://www.worldcat.org/title/top-secret/oclc/11343935&referer=brief_results
    http://www.amazon.com/Top-Secret-James-Reynolds/dp/0553154761/ref=sr_1_1?ie=UTF8&qid=1345670338&sr=8-1&keywords=top+secret+james+reynolds

    2) I miss Zubrowka. I have never been so sozzled in my life as the day I was introduced to it. I suppose the coumarin in it (yes really) amplifies the effect of the alcohol.

    3) with all the talk of printable meat I’m sure/I hope someone’s working on printable aphidflesh then ( :

  3. Entirely cool. Reminds me of being told by a fellow biology grad student in about 1978 that there HAD been a tribe of photosynthetic people, who wandered around Africa somewhere, I think the Sahara. Don’t remember when he said it was. He knew someone who knew someone, etc etc etc. It was all conveniently vague, but imagining green people around an oasis was irresistible.

  4. Very cool. I wouldn’t mind some gene tweaks to improve energy efficiency in my body.

  5. Way back when, you know…before… A buddy of mine had the job of attempting to connect scientists with inventors for the purposes of alternative energy. I once asked him which one he found the most promising. Given algaes intake of CO2, the fact that after oil extraction it can be put back in the water and go at it again, can be genetically modified to operate even in colder climates (albeit much slower), it had to be “it.” The–or a–process patent is owned by a Texan makeup millionaire. Supposedly, when the idea was hot and got some coverage in the NYT, he said all he needed was four years and $8 million (yes, with an m) to get a working prototype (or it might have been 8 and $4M, but even at 10 and $80M it would seem worth it). The geeky conversation about what could go wrong wound up, as I recall, with algae becoming self-aware and us bipeds having to defend ourselves with flamethrowers (a la The Thing) until we of course ran out of fuel.

    When I asked why the project wasn’t happening he said that if we (I think he meant Wall Street) had taken the same attitude towards computing back in the 70s that we do alternative energy today, we would still not have PCs.

    Anyway, I’m so curious about this “you are what you eat” phenomenon. How in the nine hells does one organism absorb and start using another’s genes? Sort of borrowing another’s organs (mitochondria or whatever), sure. Sounds like something you’d dream up as a kid but would later think is impossible without a virus cutting and splicing the code.

  6. This puts a whole new twist on “little green men”, doesn’t it?

    I mean, if you could just walk around (almost) naked and get your energy from any available light source, with an extra bite of nutrients every other week, green tinted skin would be a small price to pay.

  7. Just another science fiction story about photosynthesis in humans is “Village of the Chosen” by Alan Dean Foster: A journalist is spotting an emerald-green woman at a marketplace in a remote African area, following her to a village, meeting the local mad scientist — infecting him, too.

    Lateral gene exchange between parasitic lampreys and fishes they feed from: http://gbe.oxfordjournals.org/content/early/2012/08/09/gbe.evs069.full.pdf+html

  8. Neat. Thanks!

  9. Andrea_A:

    Lateral gene exchange between parasitic lampreys and fishes they feed from: http://gbe.oxfordjournals.org/content/early/2012/08/09/gbe.evs069.full.pdf+html

    Man, that is crazy. Possibly parasite-host transfer. Vampire fish!

  10. If we consider ciliates to be animals (I do, but I am biased) then the ocean is full of photosynthetic animals (oligotrichs). But I don’t recall if they merely sequester chloroplasts from prey or if they are born with them. OK, I know that protozoans aren’t born.

  11. Terry:
    Entirely cool. Reminds me of being told by a fellow biology grad student in about 1978 that there HAD been a tribe of photosynthetic people, who wandered around Africa somewhere, I think the Sahara. Don’t remember when he said it was. He knew someone who knew someone, etc etc etc. It was all conveniently vague, but imagining green people around an oasis was irresistible.

    That was Barsoom. ;)

  12. I personally like Mr. Williams take:

    http://web.archive.org/web/20110720074447/http://www.asimovs.com/_issue_0501/leopardplague.shtml/

    I don’t want to think about how many other scientific assumptions-shattering species have gone extinct long before we could discover them due to anthropogenic environmental degradation. The world’s biosphere is growing poorer by the day and we lost countless life-improving/-saving innovations that would’ve resulted from these findings…

  13. There was a piece on the radio this morning about getting bacteria to chew up lignin-heavy biomass for ethanol. Really charming to think of that trick getting loose in the wild, isn’t it?

  14. jackd:
    There was a piece on the radio this morning about getting bacteria to chew up lignin-heavy biomass for ethanol.Really charming to think of that trick getting loose in the wild, isn’t it?

    In Phantoms by Dean R. Koontz (and I think it was a movie as well) they used something like that to kill the blob thingy that, in the story, turned out to have been responsible for the Roanoke colony disappearing. It acted a bit like Carpenter’s thing otherwise as I recall.

  15. I remember a green man held captive in a circus side show (or something like) in one of the volumes in Gene Wolfe’s Book of the New Sun. The man was a photosynthesizing time traveller from a future far ahead of the (far future) earth setting of the novels. Symbiosis with algae? It’s been years since I read those books, so I can’t remember if that was clear in the text, or if it just makes sense to me now as I remember the character.

  16. The surface area just doesn’t work out though. An adult human needs 2800 kcal a day, which is 11.8MJ. Insolation at 950W/m2 at the equator. So if you lie out in the sun, your own exposed surface area is (rough guess here) 0.75m2, you’re getting about 3 MJ incident energy for every hour you spend sunbathing.

    What that means is that if you’ve got a total conversion efficiency of solar energy to metabolically usable energy of 25% (and good luck with that!) you will still have to sunbathe for sixteen hours a day to survive. And unfortunately the sun’s only up for 12.

  17. @Whoever. who wrote in-part: How in the nine hells does one organism absorb and start using another’s genes?

    I’d say “google for ‘transposonation’” and just ignore the first 10 or so uses of the phrase which happen to have me as the writer. I should be the first to inform you that I have no idea exactly whereof I speak (link to cool weirdness not mine), but if I recall correctly, “transposons” were a fairly early discovery in genetic manipulation, gave rise to some interesting new crop strains (if memory serves). See also this link (EP 0726317 B1 (granted european patent, “Bacillus-derived transglutaminase”) and view the fulltext, searching within for “transposonation”.

    Evidently transposonation occurs in nature with some frequency, for example one strain of microbes might exchange genetic material with a quite different variety of microbes, and both would wind up with the same mechanism for avoiding antibiotics, etc.

  18. Cool, thanks.

    It’s just that this also might throw the whole family tree out of whack. What we denote as one species evolving into another might actually be a mistake if this principle has happened a lot and that is the explanation for the shared code rather than descendancy.

  19. There’s some fairly old story, Frederik Pohl, I think, that I seem to recall was anthologized a few places by the early 1970s. It was one of those stories on the theme “grad students pull an elaborate prank which, when you think about it, might be a bit closer to the truth than anyone would believe under the present state of knowledge”.

    Spoiler alert, skip past this if you don’t want to know.

    Basically, the grad students are convincing a pre-grad that much of the state of modern humanity can only be explained if one posits that somehow a lot of human differences from the rest of the great apes are the result of genetic combination with pigs. Yes, swine, porkers, bacon-on-the-hoof. They go through quite a list of things that swine and humans have in common which aren’t in any of the apes, and there would have had to be some really odd and rapid evolution going on which isn’t in the same direction as the rest of the apes (and our ancestors) previously had. Let’s see: vermiform appendix, wisdom teeth, etc etc., not to mention pink skin. ;) The joke is when they bring in this pre-med student and have him do a blind work-up on an infant suspiciously named “child Porker”. Of course, until the med-student discovers the hooves, he thinks he’s working on a human infant and everything he prescribes works just fine… because pigs and people are so similar. (Yet we eat them, don’t we, was a subtext, if I correctly remember this.)

    So, we all seem to know that eurasian humans have such a wide panoply of immunity to diseases that probably jumped species from our domestic animals, while New World humans had no such immunity, the rationale being that because they didn’t have the animals they were not exposed to the diseases.

    I wonder how someone would test the hypothesis that this wasn’t the sole reason, and that we might actually have the immunity to these disorders more because of transposons for immunity jumping between the species? Because, seriously, if you had no resistance factors in the immune system, repeated exposure to novel species-jumping organisms is probably going to kill you before you somehow suddenly evolve a way to deal with it on the cellular level.

    And BTW: I must have missed something, but didn’t anyone else think that Peter’s fiblet was pretty cool, especially that bit with the Spontaneous Human Combustion, with the galoshes with charred bones sticking out of them? Heh. I wonder if “flagil” could have prevented that.

  20. Andrea_A: Lateral gene exchange between parasitic lampreys and fishes they feed from

    Holy. Shit.

    ajay: What that means is that if you’ve got a total conversion efficiency of solar energy to metabolically usable energy of 25% (and good luck with that!) you will still have to sunbathe for sixteen hours a day to survive.

    Yeah, there’s a reason no one ever lost a foot race to a philodendron. OTOH, photosynthesis could conceivably top you up and give you a bit of an edge — more of a health supplement than a meal replacement. That’s how I envisioned it in Starfish, at least.