Your Inner Fly: Fighting dipterans share genes with you and me

Introductory note by JAC: Matthew has produced a terrific post here, and I hope people will read it. The results of this scientific analysis are amazing and the genetic tools required to produce them are breathtaking—tools I couldn’t have imagined were possible when I was a graduate student. If I had one hope for 2014, it would be that more people would read the science posts. (Maybe you do, but just don’t comment on them!) kthxbai

******

by Matthew Cobb

In 2007, the genomes of 12 closely-related Drosophila species were published in Nature. This was an important moment because it enabled researchers to look beyond their traditional friend, D. melanogaster, and to study the similarities and differences between the behaviour and genes of ‘the’ fly and those of its relatives, for some species had separated only a million or so years ago, while others were much more distant: up to 40 million years of divergence.

Accompanying the genomes was a thought-provoking review by Drosophila neurobiologist Leslie Vosshall from Rockefeller University. In her article, entitled ‘Into the mind of the fly’, Leslie summarised the varied behavioural studies that had been made on Drosophila, most of them deriving from the work of Seymour Benzer, who was behind the discovery of the first biological clock gene as well as mutations affecting learning. Not only did such complex behaviours and genes exist,  it turned out that they are highly conserved: the same genes control fly clocks that control part of the human biological clock, for example. In other words, you share some really interesting bits of your physiology with a fly.

Leslie concluded her article with this bold statement:

 It now seems possible to approach in the fly more complex behaviours and even emotions, the neurobiological basis of which are not well understood at the genetic or functional level in any animal: sociality, common sense, altruism, empathy, frustration, motivation, hatred, jealousy, peer pressure, and so on. The only a priori limitation to studying any of these traits is the belief that flies can show such emotions and the design of a plausible behavioural paradigm to measure them.

At the time I thought this was fly-neuroscience hubris. But I now think she was probably right – all of our specific genetically-influenced human characters must have some vague predecessor in animals; many of those may have deep evolutionary roots, and may therefore be shared even by quite distant relatives such as flies.

One indication that Leslie was right is a paper that’s just appeared in Cell from one of her ex-students, Kenta Asahina, working in the lab of David Anderson.  Asahina, Anderson and their colleagues have shown that the biochemical basis of aggression in flies appears to involve a neuropeptide that is also involved in aggression in mammals, including humans.

Drosophila flies are normally a pretty peaceful bunch, spending their time hanging around on rotting fruit, mating and so on. But if you give a couple of males a limited amount of food, then they can get very aggressive and apparently territorial, as shown in this neat video from Amber McCartney (it goes on for nearly 4 minutes – you’ll get the idea after 15 seconds or so; at around 2:15 a female turns up, but the guys are initially more interested in beating the crap out of each other than in flirting with the gal, who isn’t up for it anyway).

The aggression is shown primarily by male flies and involves chemical signals – if you create a female fly covered in male pheromones (this is the kind of thing fly scientists love doing) the male treats her aggressively rather than trying to mate with her. The cells that are involved in controlling this behaviour express a gene called fruitless, which is very complex – it has different forms in males and females – and does lots of things to do with sex-specific fly behaviour.

Kenta and his colleagues (most of them from Cal Tech) did a neat experiment; they reasoned that neuropeptides might be involved in controlling aggression in flies, because these substances are also found in the neural circuits that control other complex behaviours. They then took 40 fly lines, representing a total of around 20 neuropeptide genes, and engineered them so that the genes would only work at 29º C (this is also the kind of thing that fly people like doing). They put males together in pairs at eclosion (hatching from the pupal case), and then automatically observed their movement.

On Day 6 they shifted the temperature to 29ºC and observed what happened. As the figure shows, two of these lines expressing a neuropeptide called Tachykinin showed high levels of lunging behaviour (this is a key part of male aggression), suggesting that this neuropeptide is involved in controlling aggression.

Fig1

They then looked at the way the Tachykinin (‘Tk’) gene was expressed in the brains of the flies and found that only a small number of cells in male flies expressed this gene. It turned out that these cells were also specific for the male form of the fruitless gene. This figure shows you the exquisite science neuroanatomists can do these days – the green labels Tk-expressing cells in the fly brain, while the magenta shows the pattern of male fruitless expression (A2, B2).

Fig2

To prove that these cells are actually involved in controlling aggression, they then manipulated the flies so they could turn the Tk on and off only in those specific cells. Sure enough, they found that when the gene was turned on, the flies showed aggressive behaviour.

There’s a whole lot more in the paper, including showing that only aggression was affected, that a mutation in the Tk gene abolished aggression, activating the Tk cells made the flies aggressive and so on, but for the general reader we can proceed to the pièce de résistance. (My apologies to the scientists who did so much work, don’t mean to belittle your effort!)

In the Discussion, the authors highlight that what fly folk call Tachykinin is homologous to what in mammals is called ‘Substance P’, which is involved in controlling aggression in mammals. In other words, the neuropeptide that enables these flies to be aggressive is also found in you and me. The authors go on to make some bold claims for what is an incredibly detailed and well-argued study. Claims that a few years ago I might have dismissed, but now take extremely seriously. I’ve reproduced the final paragraphs here, without the references. Some of it might be hard going, but this is terrific stuff, with potentially massive implications, if they are right:

Among three species of vertebrate Tachykinin neuropeptides, Substance P has been implicated, directly or indirectly, in various forms of aggression, including defensive rage and predatory attack in cats, and intermale aggression in rats. Although not all functions of Substance P are necessarily conserved (such as nociception in mammals and olfactory modulation in the fly), these data suggest that this neuropeptide is broadly involved in the control of agonistic behavior in both vertebrates and invertebrates. They therefore add to the growing list of neuropeptide systems that show a remarkable evolutionary conservation of functions in the regulation of innate “survival behaviors” such as feeding and mating. Biogenic amines also control aggression across phylogeny. However, in the case of serotonin, the directionality of its influence is opposite in flies and humans.

Our findings indicate that studies of agonistic behavior in Drosophila can identify aggression-regulating genes with direct relevance to vertebrates. Interestingly, in humans, the concentration of Substance P-like immunoreactivity in cerebrospinal fluid has been positively correlated with aggressive tendencies in patients with personality disorders. Substance P antagonists have been tested in humans as anxiolytic and antidepressant agents, although they failed to show efficacy. The present findings, taken together with mammalian animal studies, suggest that it may be worthwhile to investigate the potential of these antagonists for reducing violent aggression in humans.

References

Leslie B. Vosshall (2007) Into the mind of a fly Nature 450:193-197 (FREE!)

Kenta Asahina et al. (2014) Tachykinin-Expressing Neurons Control Male-Specific Aggressive Arousal in Drosophila. Cell 156:221-235. (abstract free, article = $$$)

149 Comments

  1. Barry Lyons
    Posted January 19, 2014 at 10:24 am | Permalink

    Whoops! Typo: that second “learning” in the second paragraph.

    • Barry Lyons
      Posted January 19, 2014 at 10:49 am | Permalink

      Well, I read this piece, and it appears to be pretty big news. I also enjoyed that video of the two male flies duking it out. Love it when the female arrives: “Hey, what’s going on? Ah, stupid males are at each other again. Screw this. I’m leaving.”

      Okay, a proposed remake of “The Fly”: the scientist doesn’t cross his genes with a fly’s by accident. This time some scientist finds a way to tap into a person’s “inner fly” and then accelerate and amplify that aspect. Maybe a Frankenstein-like scenario? The good doctor creates human fly monsters?

      I want a manuscript on my desk by the first of summer. We can worry about casting later.

      • Diana MacPherson
        Posted January 19, 2014 at 12:03 pm | Permalink

        I like how they’re pounding on each other so much that they actually knock into her.

      • wnwd
        Posted January 19, 2014 at 4:54 pm | Permalink

        Jeff Goldblum Explained at last?

  2. Posted January 19, 2014 at 10:27 am | Permalink

    Very nice study. Of course, the human homolog of fruitless must be “free will”. Just kidding.

  3. Posted January 19, 2014 at 10:31 am | Permalink

    Personally, I read them: albeit so, so slowly.slowly.slowly.

    And although I know of, passionately believe in and, for graduate study’s years’ and years’ worth, myself used the scientific method … … I also know that: I am not intelligent enough to make comment on .any. of your website’s such posts.

    Blue

    • Merilee
      Posted January 19, 2014 at 11:16 am | Permalink

      Sub

    • Posted January 19, 2014 at 11:43 am | Permalink

      I am glad that you share the passions! I call having a keen interest in science for its own sake ‘the spark’, and it is a rare and valuable thing. I keep coming back here for the science and the good company.

  4. Diana MacPherson
    Posted January 19, 2014 at 10:39 am | Permalink

    The Fighting dipterans might be a nice name for a sports team. :)

    Sure, controlling human aggression is important but I’d like a body spray form of “fruitless”. Make it for females who don’t want to be bothered with chatting up.

    • aspidoscelis
      Posted January 19, 2014 at 12:18 pm | Permalink

      The only problem with calling a team the “Fighting Dipterans” is that most fans would inevitably mispronounce it. The “pt” is a digraph, not a sequence of two separate phoneme–hence pronounced “di-teran” not “dip-teran”.

      (We needed a new pronunciation over which to quarrel after the great gif debacle, right?)

      • Posted January 19, 2014 at 1:45 pm | Permalink

        Like the silent “p” in “archaeopteryx”?

        /@

        • Diana MacPherson
          Posted January 19, 2014 at 1:50 pm | Permalink

          Yeah, the way I was taught Ancient Greek is you pronounce the p & t.

          • Gregory Kusnick
            Posted January 19, 2014 at 2:13 pm | Permalink

            I never learned Ancient Greek (or any other kind) but from a plausibility standpoint it seems unlikely that “pt” and “t” should represent the same sound.

            For what it’s worth, typing “wing” into Google Translate yield φτερό, which to my ear sounds roughly like “phthero”.

            • Diana MacPherson
              Posted January 19, 2014 at 4:03 pm | Permalink

              φτερό = pstero puh-s-tero (eventually this became) πτερό

              Labials are lip sounds = p or π
              Dentals are teeth sounds = t or τ

              Here is how Smyth (one of the best Ancient Greek grammar books) describes it:

              STOPS BEFORE STOPS

              A labial or a palatal stop before a dental stop (τ, δ, θ) must be of the same order (16).

              Stops (or mutes). Stopped consonants are so called because in sounding them the breath passage is for a moment completely closed. The stops are divided into three classes (according to the part of the mouth chiefly active in sounding them) and into three orders (according to the degree of force in the expiratory effort).

              In other words you pronounce all the letters and a pt combination is a stop before a stop.

              I believe this holds for modern Greek as well.

          • aspidoscelis
            Posted January 19, 2014 at 3:38 pm | Permalink

            Well, if you can pull off an initial “pt” as two separate consonants with no vowel, go for it. :-) So far as I can tell, it’s usually simplified to “t” because this alternative is exceedingly difficult to pronounce (I’m not even sure what it’s supposed to sound like, personally). Either way, the “p” goes with “teran”, not “di”. There ain’t no “dip” in “dipteran”.

            • Diana MacPherson
              Posted January 19, 2014 at 4:05 pm | Permalink

              dip-teran. It’s easy just like archaeop-teryx.

            • Gregory Kusnick
              Posted January 19, 2014 at 11:51 pm | Permalink

              “Waiter, there’s a dipteran in my dip!”

            • Posted January 20, 2014 at 10:42 am | Permalink

              So you find it exceedingly difficult to pronounce both the p and the t in “helicopter”? I don’t. :D

              • aspidoscelis
                Posted January 20, 2014 at 10:53 am | Permalink

                Try it without joining the “p” to the preceding “o” as a single syllable.

              • Posted January 20, 2014 at 11:01 am | Permalink

                Easy, no problem.

              • aspidoscelis
                Posted January 20, 2014 at 11:03 am | Permalink

                I don’t believe you. :-)

              • Posted January 20, 2014 at 11:08 am | Permalink

                No leap of faith necessary. I have no difficulty pronouncing it at all. Perhaps it is because I am multilingual, or something. I do have a talent for being able to accurately reproduce foreign words of all kinds and origins after one, two or three trials, and sometimes at the first attempt. Must be the musician that I am. Having grown up in several languages simultaneously also could be a reason.

              • Posted January 20, 2014 at 11:09 am | Permalink

                Just purse your lips and blow… ;)

              • wnwd
                Posted January 20, 2014 at 2:28 pm | Permalink

                Perhaps the example word here is: perturbed… or, for some, p’turbed :-P

          • gravelinspector-Aidan
            Posted January 21, 2014 at 4:02 pm | Permalink

            Yeah, the way I was taught Ancient Greek is you pronounce the p & t.

            … and, as when you correctly pronounce “Groningen”, you then wipe the faces of the audience clean.

        • Posted January 19, 2014 at 1:55 pm | Permalink

          …and in pterodactyl.

          • gbjames
            Posted January 19, 2014 at 1:57 pm | Permalink

            And Pteranodon.

            • Posted January 19, 2014 at 1:58 pm | Permalink

              …and so on. :D

            • Diana MacPherson
              Posted January 19, 2014 at 2:00 pm | Permalink

              ….and baptize.

              • Posted January 19, 2014 at 2:07 pm | Permalink

                Not really… http://oald8.oxfordlearnersdictionaries.com/dictionary/baptize

              • Diana MacPherson
                Posted January 19, 2014 at 3:39 pm | Permalink

                Yes. I’m arguing that pt is pronounced separately. As in archaeopteryx.

                Baptize was facetious however.

              • aspidoscelis
                Posted January 19, 2014 at 3:46 pm | Permalink

                So how would you pronounce “Pteris“? “Puh-teris”?

              • Diana MacPherson
                Posted January 19, 2014 at 4:17 pm | Permalink

                Yes. It’s a stop before a stop. It’s easier than pf in German as in pflegen.

              • aspidoscelis
                Posted January 19, 2014 at 4:24 pm | Permalink

                The German “pf” is easy. :-)

                However, if “Pteris” is “puh-teris”, then “dipteran” is “di-puh-teran”. I’ll stick with simplifying “pt” as “t” on the grounds that this alternative sounds unnecessarily silly, while the “dip” alternative is etymologically incoherent. There is no “dip”-containing root here.

              • Diana MacPherson
                Posted January 19, 2014 at 4:27 pm | Permalink

                You’d pronounce it dip-teran. Not dipuh teran. It’s how you pronounce it which has nothing to do with etymology. That’s like saying if I pronounce helicopter as heli-copter it’s wrong because there is no such thing as a copter or that the letter p is wrong because it’s pronounced “pee”.

                The point is, pronounce it how you want but know that it’s inaccurate and telling others they are pronouncing it wrong when they say dip-teran is inaccurate because they are actually pronouncing it correctly. It’s not English, it’s Ancient Greek.

              • aspidoscelis
                Posted January 19, 2014 at 4:38 pm | Permalink

                It’s not Ancient Greek, either. It’s scientific, Latinized, Ancient Greek, for which there are two applicable standards we might use: either pretending the “p” is part of the previous syllable (which obscures etymology but is typically done when the “pt” is internal) or making the “p” silent (which is a pretty universal standard for an initial “pt”). Since the first alternative has multiple flaws (obscuring etymology and not being universally applicable–you can’t do it with an initial “pt”, so you need separate initial and internal “pt” rules) while the second can be applied consistently, clarifies etymology, and can only be faulted for not following the pronunciation rules of Ancient Greek (which, while the source language for the roots used, is not the realm in which these words currently reside). Hence pronouncing “pt” as “t” is the correct solution.

              • Diana MacPherson
                Posted January 19, 2014 at 4:47 pm | Permalink

                nope.

              • Posted January 19, 2014 at 4:50 pm | Permalink

                @ aspidoscelis

                So you think “helicoter” and “archeoteryx” are correct?

                I think you‘re taking the “p”!

                /@

              • aspidoscelis
                Posted January 19, 2014 at 4:54 pm | Permalink

                Ant Allan-

                Regarding “Archaeopteryx” – yes.
                Regarding “helicopter” – well, that’s English and therefore a lost cause.

              • Posted January 19, 2014 at 5:08 pm | Permalink

                I think youll find that Archaeopteryx is also English. Certainly the editors of the OED seem to think so!

                /@

              • aspidoscelis
                Posted January 19, 2014 at 5:14 pm | Permalink

                Treating scientific names as English words would require substantial change to the nomenclatural codes, if nothing else! The editors of the OED may know many things, but why one should trust them on matters of scientific nomenclature I do not know.

              • Posted January 19, 2014 at 5:59 pm | Permalink

                I think they might know a bit more about language and linguistics than the average scientist!

                In any case, my point was that Archaeopteryx is as much an English word as helicopter and, amongst the vast majority of anglophones, the p is given the same value. Youve already lost here, too.

                /@

              • aspidoscelis
                Posted January 19, 2014 at 8:37 pm | Permalink

                The OED is run by descriptivists; they’ll bless anything so long as they can cite someone having done it.

                But, no, “Archaeopteryx” is not an English word. You may as well call “je ne sais quoi” an English phrase, on account of English speakers have used it.

              • Posted January 20, 2014 at 11:16 am | Permalink

                Exactly the point: You’ve lost.

                So, is “bungalow” an English word? “Hoi polloi”? “Eggs”?*

                And I may be wrong, but I do think that “je ne sais pas” is English; the way it is used in English — “this has a certain je ne sais pas” — differs from how it is used in French — simply, “I don’t know.” (Francophones please confirm/refute.)

                /@

              • Diana MacPherson
                Posted January 20, 2014 at 11:20 am | Permalink

                I think you’re thinking of je ne said quois.

              • Posted January 20, 2014 at 11:27 am | Permalink

                Eep. Mea culpa!!

                Then Im confused, as “je ne sais pas” isnt a phrase used in English, afaik. So, I think I must have subconsciously thought that “je ne sais quois” was what our interlocutor was thinking off

                /@

              • Posted January 20, 2014 at 11:50 am | Permalink

                Un petit je ne sais quoi.. “je ne sais quoi” = I don’t know what.

              • Posted January 20, 2014 at 11:48 am | Permalink

                C’est exactement ce que cela veut dire… ooops, sorry… that’s exactly what it means!

              • Posted January 20, 2014 at 1:14 pm | Permalink

                Ah, but I was getting muddled I dont know if you can decipher the thread, which has probably gone on too long anyway

                /@

              • Posted January 20, 2014 at 11:20 am | Permalink

                * A foreign word for “eyren” until the sixteenth century.

              • Diana MacPherson
                Posted January 20, 2014 at 11:22 am | Permalink

                Oops, “je ne sais quois” (damn you autocorrect).

              • Posted January 20, 2014 at 11:51 am | Permalink

                Pssst! The word “quoi” doesn’t take an s at the end. :)

              • Diana MacPherson
                Posted January 20, 2014 at 11:53 am | Permalink

                I can’t type French on this phone. I never installed other languages so it is a fight each time. I out German on my other one and now both languages fight each other so some people get bizarre German words as their answers.

              • Posted January 20, 2014 at 11:58 am | Permalink

                You’re connected via a phone? I could never use a phone, however “smart”, to type anything. Their “keyboards” are way too small for me, as are their screens. Hats off to you!

              • Diana MacPherson
                Posted January 20, 2014 at 12:01 pm | Permalink

                Yeah. But other times my mistakes are just my own. :)

              • Posted January 20, 2014 at 12:03 pm | Permalink

                ALL my mistakes are my own. I especially like the ones nobody else made before I did! :D

              • Posted January 20, 2014 at 1:17 pm | Permalink

                Noted. M. Wainwright would be ashamed of me.

                /@

              • Posted January 20, 2014 at 11:31 am | Permalink

                ** Oh, for an Edit function!

              • Diana MacPherson
                Posted January 20, 2014 at 11:33 am | Permalink

                I hate it when you see your mistake while it is publishing. That’s such torture!

              • aspidoscelis
                Posted January 20, 2014 at 1:23 pm | Permalink

                vierotchka wrote:
                “Pssst! The word “quoi” doesn’t take an s at the end. :)”

                Well, it doesn’t in *French*; as an English word one can presumably spell & pronounce it however one likes. :-)

            • Posted January 19, 2014 at 2:16 pm | Permalink

              …and helicopter :P

        • aspidoscelis
          Posted January 19, 2014 at 3:22 pm | Permalink

          Exactly. Everyone gets that one wrong, too. :-)

          In botany, this pops up frequently in fers: pteridophyte, Pteris, Pteridium, Dryopteris, Cystopteris, Thelypteris, etc.

          • aspidoscelis
            Posted January 19, 2014 at 3:22 pm | Permalink

            “Ferns”, that should be. Augh.

          • Diana MacPherson
            Posted January 19, 2014 at 3:39 pm | Permalink

            It’s the scientists who have it wrong.

            • aspidoscelis
              Posted January 19, 2014 at 4:39 pm | Permalink

              I think the ancient Greeks had it wrong. :-)

        • thh1859
          Posted January 19, 2014 at 5:14 pm | Permalink

          Or silent p in bath.

          • abrotherhoodofman
            Posted January 19, 2014 at 5:40 pm | Permalink

            lol

    • gravelinspector-Aidan
      Posted January 21, 2014 at 4:00 pm | Permalink

      The Fighting dipterans might be a nice name for a sports team.

      Sounds like a biplane formation flying team to me.

      • Diana MacPherson
        Posted January 21, 2014 at 4:37 pm | Permalink

        Yes! That would work too!

  5. Vicki
    Posted January 19, 2014 at 10:39 am | Permalink

    I read many of them, but there doesn’t seem to be much point to comments that just say “interesting” or “thanks.” And that’s probably influenced by my being annoyed that on almost every post, the first few comments are content-less, I guess so the person will be notified of the actual comments.

    • Kevin Alexander
      Posted January 19, 2014 at 11:10 am | Permalink

      I read them too. I just don’t usually comment since I’m not qualified and any question I might ask would be embarrassingly stupid.

      • Posted January 19, 2014 at 12:46 pm | Permalink

        How do you think those who are qualified made their way from your level of ignorance to their qualifications if not by asking embarrassingly stupid questions?

        Ask away! If nothing else, rest assured that there’re those of us even more ignorant than you who’ll also benefit from the answers.

        Cheers,

        b&

        • John Taylor
          Posted January 19, 2014 at 5:17 pm | Permalink

          OK. How do they get the flies to lie still while they scan their brains? I’m imagining that a fruit fly brain is pretty tiny. How the heck does one scan a fruit fly’s brain?

          • abrotherhoodofman
            Posted January 19, 2014 at 5:45 pm | Permalink

            They’ve gone even smaller… a LOT smaller.

            (Apologies for linking to a Fox News website, but the story is there.)

          • Keith
            Posted January 20, 2014 at 6:31 am | Permalink

            John: the flies are anesthetized with carbon dioxide. Fly researchers pump the gas through a membrane that serves as a stage for sorting and manipulating the animals. Shut off the flow of gas, and they wake up after a minute or so.

            • Diana MacPherson
              Posted January 20, 2014 at 8:01 am | Permalink

              In high school, I overdid it and killed all my flies. Good thing I didn’t want to be an anesthesiologist.

  6. gbjames
    Posted January 19, 2014 at 10:42 am | Permalink

    sub

  7. gbjames
    Posted January 19, 2014 at 10:42 am | Permalink

    sub

    • gbjames
      Posted January 19, 2014 at 10:42 am | Permalink

      hmm… why did that happen?

      • Diana MacPherson
        Posted January 19, 2014 at 10:44 am | Permalink

        Are you replying via email? I know that if my brain sends some weird signal to my hand when I click submit, causing it to spasm an extra click, WordPress won’t let it through & tells me I already said that.

        • gbjames
          Posted January 19, 2014 at 10:50 am | Permalink

          No, I was in a browser. Perhaps an unwitting double-click.

      • Posted January 19, 2014 at 10:53 am | Permalink

        It happened to me too but in a different way (see below).

  8. Posted January 19, 2014 at 10:47 am | Permalink

    There could be a little quiz at the end of science posts which may generate discussion.

  9. Posted January 19, 2014 at 10:51 am | Permalink

    Good to know… that explains a lot… sommebody help me…

    • Posted January 19, 2014 at 10:52 am | Permalink

      Someone please delete this above comment, the proper comment is below. I don’t know how it happened, I was correcting my spelling mistake when it suddenly posted instead. Thanks. :D

  10. Posted January 19, 2014 at 10:51 am | Permalink

    Good to know… that explains a lot… somebody help me…

  11. Jesper Both Pedersen
    Posted January 19, 2014 at 10:58 am | Permalink

    I’m a bit on thin ice here, what might the major implications of this be?

    • Torbjörn Larsson, OM
      Posted January 19, 2014 at 2:49 pm | Permalink

      Another win for “There Ain’t No Such Thing As A Free Will” (TAINSTAAFW, to rip off a popular adage).

      Or maybe a promise for aggression control, for better or worse.

      Or “just” a find that animals are closely related.

      • Jesper Both Pedersen
        Posted January 19, 2014 at 2:55 pm | Permalink

        Maybe it’ll trigger a “Scopes Worm” trial.

        That would be fun.

    • abrotherhoodofman
      Posted January 19, 2014 at 3:54 pm | Permalink

      Implications? Here is a guess.

      Studies like these provide evidence that some important aspects of human behavior (i.e. anger) and its associated brain functionality can be studied effectively in species like Drosophila Melanogaster.

      In other words, fly brains can be used to study human brains. For legal reasons, nobody is allowed to study human brains in a manner that might potentially harm the human. The same doesn’t apply for insects, so the studies can go much, much deeper.

      Decades from now, a “more peaceful” humanity may end up owing the lowly fly a serious debt of gratitude!

      • Diana MacPherson
        Posted January 19, 2014 at 4:20 pm | Permalink

        The entire time I was reading this article, I kept thinking of the Firefly movie, Serenity where they go to Miranda.

        • Jesper Both Pedersen
          Posted January 19, 2014 at 4:23 pm | Permalink

          That was a pretty good flick even though the preacher was a pain in the butt. :-)

          • Diana MacPherson
            Posted January 19, 2014 at 5:34 pm | Permalink

            ….and what happened to Wash. “I am a leaf on the wind….”

      • ROO BOOKAROO
        Posted January 20, 2014 at 5:30 am | Permalink

        abrotherhoodofman:

        A “more peaceful” humanity will probably never happen. Not in decades, not in centuries.

        If the aggression gene has survived millions of years to reach us, no way it will vanish according to your dreams. It is part of us, and a moral judgment is irrelevant and won’t change our DNA makeup.

        When the aggression gene did change, it did in different branches of mammals, it created sheep or cows. But not border collies, or big apes. Our lines have diverged through apes and chimpanzees, all famous for their aggression instincts. We’re stuck with it, and the best we can do is learn how to manage it.

        And, further, who would like to live in a “peaceful humanity”. It’s another Christian dream, all of us sitting on our clouds, listening to the white-bearded boss reminding us of obeying our commandments, while in the background Mozart is directing the angels choir.

        What a boring life! No dispute, no criticism, only blissful harmony and boring peace. Who wants this kind of flock-like existence? Only priests and Big Brother as in 1984. Science and scholarship would die on the root. As it did in some ways during the Stalinist period, and now in Muslim theocracies.

        • Posted January 20, 2014 at 11:11 am | Permalink

          I think many of us would consider a more peaceful future to be one without war, or rape, or murder.

          Are you actually saying that would be boring? I think I have much more faith in humanity than you do (and that’s definitely NOT part of a “Christian dream”).

          Hasn’t Sam Harris already been showing us that humans are already less violent than we once were. Flock-like? Certainly not.

          More important, doesn’t understanding where aggression comes from allow us the knowledge we need to work to overcome such feelings?

        • gravelinspector-Aidan
          Posted January 21, 2014 at 4:28 pm | Permalink

          If the aggression gene has survived millions of years to reach us,

          They’re quite explicitly not talking about “an” aggression gene, but several genes in different parts of the organism’s genomes which lead to the expression of different proteins.
          What is surprising is that these genes appear to have passed down from very distant ancestors (flies are ecdydozoans – they moult ; we have internal skeletons ; but at least we’re both bilaterally symmetrical, not like those weird “coral” things) to both of the two sets of descendants, and they are still involved in similar behaviours.

          When the aggression gene did change, it did in different branches of mammals, it created sheep or cows.

          They examined the effects of these genes in both rats and cats (and I suspect that there would be other evidence for their effects in other branches of the mammalian clade ; but I don’t have the full papers to search more deeply). Sheep and cows are very closely related by comparison to that phylogenetic spread.

          • ratabago
            Posted January 21, 2014 at 7:17 pm | Permalink

            Sheep and cows are special values of $banana. We breed them to be docile and easily manageable. The wild strains were quite aggressive.

  12. Posted January 19, 2014 at 11:01 am | Permalink

    Fascinating.

    /@

    • Occam
      Posted January 19, 2014 at 12:40 pm | Permalink

      _\\// (or U+1F596 in Unicode 7)

  13. Hempenstein
    Posted January 19, 2014 at 11:05 am | Permalink

    OK, soon as I saw peptide, I wanted to know what the structure was. Not that I would really understand anything just from that, but it makes me feel better. And so I found this review article which, ‘tho a dozen yrs old, is full of structures, along with almost 400 refs. From a very quick skim, it seems that invert tachykinins are short peptides ending with a C-terminally amidated arginine, suggesting that there is a strongly anionic binding site for them in their receptor.

    With homologs from higher organisms, the peptides are longer and the signature sequence is still there at the C-terminal end (of course, there has to be a signature sequence somewhere, otherwise they wouldn’t be homologs), but the C-terminal Arg is now gone and they typically end with a C-terminally amidated Met. It looks like the Arg did not mutate to a Met, it is simply missing and now the penultimate residue relative to the invertebrate sequences (where it is Ala, Val or Met) is now the one that is amidated. If the amidation mechanism is the same as typical for other peptides, then the Arg codon most likely underwent a deletion, leaving a Met-Gly sequence at that point in the precursor, the Gly contributing the amidating nitrogen atom.

  14. natalielaberlinoise
    Posted January 19, 2014 at 11:06 am | Permalink

    I am another one who reads the science posts without much of a trace. That’s what got me hooked here: to find information about topics I slept through in school, which I now regret, and getting encouraged for my mental efforts with salutary woo bashing, kitties galore and more.

    Often questions about the Science posts occur that I don’t dare adding. The reading of comments from the savvy folk is rewarding by itself.

  15. Kevin Alexander
    Posted January 19, 2014 at 11:13 am | Permalink

    The anti-Pinker crowd will all ignore or deny depending on their Ph level.
    Agression is obviously culturally conditioned because Patriarchy.

    • ROO BOOKAROO
      Posted January 20, 2014 at 5:39 am | Permalink

      Kevin Alexander:

      How about the reverse: Patriarchy became possible as a cultural product of aggression genes in our make-up?

  16. Barbara
    Posted January 19, 2014 at 11:18 am | Permalink

    I read the science posts. In fact, I’m more likely to read them all the way through than I am to read the philosophy posts all the way through. If I posted on the science postings, all I would have to say would be “Way cool!!” again and again.

    Of course, the philosophy posts are valuable, but I read this . . . website (I was about to say blog) regularly, and after reading the first ten there-is-no-free-will or lack-of-evidence-of-god-is-evidence-of-no-god post, the next one (valuable as it is to many readers) doesn’t add a lot to what I’ve already learned. Refuting the latest supposed refutation of these ideas has value, but since the supposed refutations seem to cover the same ground again and again, so do the post here.

  17. John Taylor
    Posted January 19, 2014 at 11:25 am | Permalink

    I’m a big fan of the science posts. I just rarely have anything intelligent to add.

  18. gbjames
    Posted January 19, 2014 at 11:34 am | Permalink

    I suspect nearly all of us greatly appreciate the science posts but don’t have to expertise to add much in comments. But on the subject of religion, we’re all experts. ;)

    • Achrachno
      Posted January 19, 2014 at 1:45 pm | Permalink

      Exactly!

    • Torbjörn Larsson, OM
      Posted January 19, 2014 at 2:53 pm | Permalink

      I want to believe that is the truth.

    • gravelinspector-Aidan
      Posted January 21, 2014 at 4:29 pm | Permalink

      But on the subject of religion, we’re all experts.

      On religion, you don’t need to be an expert. Just to be opinionated.

  19. Steven Obrebski
    Posted January 19, 2014 at 11:38 am | Permalink

    I read every science post. I download it and print it out. Frequently I download and print associated material on stuff I don’t know anything about or don’t understand. But by the time I have finished reading the material its days after the post. Perhaps a posting a week from now asking for commentary on this material would indicate more exactly how it is received.

    Please keep these scientific posts coming and add more if possible.

    Posts reviewing recent findings in studies of the origin of species would be great.

  20. Posted January 19, 2014 at 11:39 am | Permalink

    I had to think of the film “A clockwork orange” where they treat an aggressive criminal.

  21. Posted January 19, 2014 at 11:42 am | Permalink

    The brain images look nice. I have no idea what they mean but the colors are beautiful.

  22. Steven Obrebski
    Posted January 19, 2014 at 11:47 am | Permalink

    I should add that the comments of John Taylor and GBJames apply to me. I got a PhD in paleozoology and taught evolution and associated subjects for years. However, now
    I need to use a recent genetics book frequently and the technical innovations used in research are beyond me. So adding anything useful to the posting would be rare.

  23. Posted January 19, 2014 at 11:52 am | Permalink

    I gobble up the science posts.
    Makes me wonder about levels of substance P and/or sensitivity to it in dysfunctional societies. This too brings up free will. Speculating here, but if you have become conditioned to have high levels of these aggression peptides, or if you become sensitive to them, then it would indeed be difficult to control violent impulses when you see a rival gang member walking down the street.

  24. NewEnglandBob
    Posted January 19, 2014 at 12:00 pm | Permalink

    I think one male fly was using the rope-a-dope tactic.

    If we could somehow find a way to turn off the human equivalent of fruitless and see what happens, then maybe world peace is around the corner. ;)

    • onkelbob
      Posted January 19, 2014 at 12:30 pm | Permalink

      Except when one mutant appears and decides he wants to rule. Or perhaps when the other apex predators recognize we turned into defenseless lunch items and they decide to to rule. Aggression in and of itself is not necessarily bad, it’s senseless aggression that leads to trouble.
      As an aside, the local Nobel candidate always tells the frau, yeah, when you are working with simple things in simple systems it is always easy to draw nice clean conclusions. However, when you are dealing with complex systems and complex organisms, your conclusions will always be subject to doubt. If you want to be published in the big 3, ignore the doubt and simply assert your conclusion is pristine. I don’t know if that is what happening here, but I suspect there is just a wee bit of handwaving going here. When I get to the lab tomorrow maybe I’ll read the paper, or maybe I’ll work on the grant… yeah I know what I will be doing. Damn fly people steal the NIH money, us mouse labs have to earn it ;^)

  25. Posted January 19, 2014 at 12:51 pm | Permalink

    It seems that we’re getting to the point where we should know quite a bit about our 800 Mya common ancestor with the fruit fly…but I, personally, don’t really have much of an idea what said great…great-granddaddy would have been like.

    Jerry, Matthew, or anybody else…can you paint any sort of a portrait? Physiologically, what would it have been like? And what sorts of behaviors / psychology / whatever would it have exhibited? What of its biochemistry? And so on….

    Cheers,

    b&

    • gbjames
      Posted January 19, 2014 at 1:32 pm | Permalink

      I went looking for the answer in Dawkins’ The Ancestor’s Tale. It would seem to be some early Protostome just after we-all parted ways with some (but not all) of the flatworms. So I guess some flat-wormy critter we can call “Gramps”.

      • Posted January 19, 2014 at 2:13 pm | Permalink

        Yep, a worm, according to Russ Hodges’s The Future of Genetics.

        /@

      • Posted January 19, 2014 at 3:10 pm | Permalink

        The hypothetical common ancestor is called the ‘urbilaterian’. Having the genes shared by bilateral animals, it might have appendages, eyes, a heart, nervous system, etc. Oh, and it apparently fight. See
        Yo mama and
        Whose Yer Daddy.

      • Charles Jones
        Posted January 20, 2014 at 7:50 am | Permalink

        It is always interesting when the origin of genes gets pushed back further and further in time. Sometimes they share a similar function, as with this post on aggression, and sometimes they are co-opted into a new function. I always want to know about the ultimate origin of a gene; it often seems to go back to the Precambrian, which the ancestor and its specific environment are both hypothetical, alas.

        I wonder if anyone has compiled a sort of family tree of interesting genes? I’ll have to start Googling…

    • Posted January 20, 2014 at 11:29 am | Permalink

      Thanks, everybody! This is why I love this place.

      b&

  26. Andrikzen
    Posted January 19, 2014 at 1:00 pm | Permalink

    I too cast my vote for the science posts and read every one – though I am eminently unqualified to comment.

    It’s unfortunate the God/religion debate has to consume so much time and energy but religious encroachment into science and the public commons must be checked and kept under quarantine.

  27. Dale
    Posted January 19, 2014 at 1:16 pm | Permalink

    I read the science posts, and philosophy posts, though of course much is over my head. I’m more inclined to ask questions but this isn’t quite the format for it.

    This post is fascinating in the sense that material evidence of a behavioral function common across distantly related species is identified clearly. Emphasis on ‘material’, ‘distant’, and ‘behavior’.

    I couldn’t help but go back and look up the GIF of the amphipod, diatom and bacteria. So cool.

  28. Alektorophile
    Posted January 19, 2014 at 1:33 pm | Permalink

    Same here. As many readers above commented, I read and quite enjoy the science posts, but they invariably being outside of my limited area of expertise (not in the natural sciences), I mostly content myself with sitting back and reading other people’s posts rather than automatically adding a useless “cool” or “that’s interesting!” comment of my own. Same goes for other categories of posts like those presenting readers’ photos, which I similarly greatly enjoy (I will have to visit Idaho one of these days!) but rarely comment upon.

    That said, cool and interesting study!

  29. Prof.Pedant
    Posted January 19, 2014 at 1:38 pm | Permalink

    These discoveries about the neuro-chemical (etc.) basis of our behavior are increasingly enabling us to consciously modify our behavior. Those conscious choices are a product of our neuro-chemical (etc.) state, producing a condition of recursive irony in which we learn to pull our own strings…and proceed to do so in accordance with how our strings are being pulled.

    As we learn to modify our desires, preferences, compulsions, hopes, dreams, inclinations, reactions, assumptions, and expectations at will I suspect that those folks who appreciate the irony of only being able to do these things in accordance with our desires, preferences, compulsions, hopes, dreams, inclinations, reactions, assumptions, and expectations, will benefit a lot more than those who insist that this knowledge enables them to be ex-puppets.

    • abrotherhoodofman
      Posted January 19, 2014 at 5:30 pm | Permalink

      Very interesting comment.

      I do have some doubts about attempting to “consciously” control things which fall into your category of reactions, such as impulsive anger, for instance. The act of being “conscious” of a certain emotion, and the actual initiation and expression of the emotion itself, might be on two completely different timescales.

      I really have no idea what the hell I’m talking about, but it seems logical given that “consciousness” appears to be an emergent, highly complex (and therefore slower to process?) property of bigger brains, that we might have to go down to the level of the genes and neurons themselves to control the baser, faster, more primitive responses.

  30. Posted January 19, 2014 at 2:36 pm | Permalink

    Maybe you do, but just don’t comment on them!

    Yes. What people like to read, and what they feel compelled to comment on can be two different things. But they could indicate their appreciation by hitting the “like” button at least, which I’ll do now. :)

  31. kelskye
    Posted January 19, 2014 at 2:39 pm | Permalink

    It’s hard to comment on science posts as really there’s not much to say for anyone who is a layman. When it comes to posts that are more political or religious, however, you’re engaging on topics where people have an opinion and can make a contribution. I do try to read the science posts, like this one, but I wouldn’t really have a need to comment on them.

    • gravelinspector-Aidan
      Posted January 21, 2014 at 4:36 pm | Permalink

      It’s hard to comment on science posts as really there’s not much to say for anyone who is a layman.

      “I didn’t understand point X ; could someone explain it to me in more detail” is always a valid comment. Many of us have worked in many branches of science over the years and are happy to help.

  32. Torbjörn Larsson, OM
    Posted January 19, 2014 at 2:40 pm | Permalink

    Undoubtedly it has been said before, but that is pretty fly.

    There’s a whole lot more in the paper, including showing that only aggression was affected, that a mutation in the Tk gene abolished aggression, activating the Tk cells made the flies aggressive and so on, but for the general reader we can proceed to the pièce de résistance. (My apologies to the scientists who did so much work, don’t mean to belittle your effort!)

    Oh, I think the general reader appreciates knowing that so much contextual work was put into testing and detailing the hypothesis, as long as it is aptly summarized! It’s the data picking of some science commenting that gets many people’s goat.

  33. Posted January 19, 2014 at 3:15 pm | Permalink

    Things that are over my pay scale here are the free will posts. Cannot remember the terminology for the pro- and anti-free will groups. When it is explained, it leaks right out again. As an old entomologist I always say ‘not enough legs’.

  34. marksolock
    Posted January 19, 2014 at 3:16 pm | Permalink

    Reblogged this on Mark Solock Blog.

  35. abrotherhoodofman
    Posted January 19, 2014 at 4:09 pm | Permalink

    If I had one hope for 2014, it would be that more people would read the science posts. (Maybe you do, but just don’t comment on them!) kthxbai

    Remember Jerry: absence of evidence isn’t necessarily evidence of absence.
    ;)

  36. Kevin
    Posted January 19, 2014 at 8:20 pm | Permalink

    ~67% of my knowledge of knowledge of biology comes form Mathew’s posts, the rest:
    ~25% comes from Jerry
    ~5% comes from Nature (PBS)
    ~2% comes from Pharyngula (almost exclusively cephalapods)
    ~1% comes from observing my cats year round and the bees and ants in summertime

    Thank you Mathew

    • Kevin
      Posted January 19, 2014 at 8:23 pm | Permalink

      I meant to say just knowledge, not to assume some modicum of Godel’s completeness theorem.

  37. Marella
    Posted January 20, 2014 at 1:31 am | Permalink

    I read all the science posts, but like so many others don’t often comment.

    My comment for this one is that if we can alter people’s brain chemistry with these peptides to make them more peaceable, we can also make them more aggressive. Armed forces might like this sort of thing perhaps. It seems like a two edged sword to me.

    Our wormy ancestor must have had occasion to wrestle with other worms for resources and mates.

  38. Posted January 20, 2014 at 6:53 am | Permalink

    I love the science posts but only comment if I think of a question or some additional content, or where I have some knowledge. The ones I feel least able to comment on are those relating to the US only, unless it has wider ramifications.

  39. Posted January 20, 2014 at 11:25 am | Permalink

    I’d love to know if the less aggressive apes have the same levels of Substance-P as humans. Or the same numbers of cells that produce it.

    • Posted January 20, 2014 at 11:52 am | Permalink

      The least aggressive apes are the Bonobos. I don’t know anything about Substance-P, though.

  40. ratabago
    Posted January 21, 2014 at 3:47 am | Permalink

    Just adding another data point here:

    – I try to read all the science posts, and at least half of the linked material, and all the associated comments. Sometimes I just can’t find enough free time to do this as completely as I would like.

    – I try to read all the articles on the efforts of CS/ID to pervert legitimate science education.

    – I do a quick scan of the more philosophical posts. I go back and read over half of them in detail.

    – I do a quick scan of the other anti-religious and atheist posts. About a quarter I will go back and read.

    – I glance at all the cat related posts. I’ll spend more time on those if I’m not busy. Similarly for the humorous posts.

    It was the science that brought me here. That and the thoughtful, and, generally, well behaved commenters are what keep me coming back.

    • Posted January 22, 2014 at 10:01 am | Permalink

      Dang, Ratabago, my WEIT reading patterns match yours almost 100%! The only difference is that I read most of the music posts and feel compelled to comment on them more than the others. That’s probably because, even though I’m not a musician, music plays an oversized role in my life.

      I emphatically agree with your last two sentences, and would like to add that I’m very grateful to Professor Ceiling Cat for his constant vigilance and reminders to keep comments civil.

      I’d love to see some posts on speciation!

  41. Posted January 21, 2014 at 7:17 pm | Permalink

    This is scary, especially if it’s replicable in humans. You can make an entire subset of population excessively aggressive without even their awareness of this aggression.

    • Posted January 21, 2014 at 7:37 pm | Permalink

      I don’t think that follows — either that people wouldn’t be able to figure out that something is worng or that it’s a substance whose misuse we need fear.

      Sure, maybe the first couple times it’s used on unsuspecting victims they might not know what’s going on; after that, people would figure it out, even if they were incapable of controlling their rage.

      I can’t imagine any modern military officer being interested in something like this for his own troops, as it would be severely detrimental to combat effectiveness. They’d be too likely to turn on each other and then refuse to stand down when ordered to. Hotheadedness is not a desired trait in a modern soldier.

      The only other option would be for it to be weaponized and dispersed against a target. First up there, you’ve got all the same problems as with any other chemical weapon, from practical to political. And then you’ve got the even bigger problem that, if you’re going to use chemical weapons, there’re much more effective ones to use than something that just makes people angry.

      Maybe some comic book supervillain would use it in a terrorist plot device, but that’s about it.

      Cheers,

      b&

  42. JBlilie
    Posted January 22, 2014 at 1:32 pm | Permalink

    Really great post and — as Jerry said — amazing tools. Holy crap!

  43. Posted May 26, 2014 at 10:49 am | Permalink

    Reblogged this on barralopolis and commented:
    This is very useful for my current Molecular Biology class. Also for anybody getting introduced to Drosophila.


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