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The Coevolution of Lice & Their Hosts 179

Posted by samzenpus
from the lets-be-adults-about-this-everyone dept.
eldavojohn writes "It might be an uncomfortable subject but parasites are an interesting subject when it comes to evolution. Ever wonder if pocket gophers have lice? Well, they do. And most interesting of all is the evolution of these lice mirroring the evolution of gophers. To study the genes of lice may shed just as much light on evolutionary trees as studying the genes of the actual host the lice has evolved to. The most unsettling result from these studies is that human head lice and human pubic lice (crabs) vary so greatly that they are in two separate genera. There were similarities between our pubic lice and the lice found on gorillas. Scientists came to the conclusion, which they published today in BMC Biology, is just as striking as their earlier one about head lice. But it is hardly the same. We did not get pubic lice from other hominids. We got them from the ancestors of gorillas."
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The Coevolution of Lice & Their Hosts

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  • by Whiney Mac Fanboy (963289) * <whineymacfanboy@gmail.com> on Wednesday March 07, 2007 @11:44PM (#18271940) Homepage Journal
    We did not get pubic lice from other hominids. We got them from the ancestors of gorillas.

    Did anyone else read that line and think that this was article could have some link to the Monkey's Uncle [slashdot.org] (proto chimp/proto human interbreeding) story from a while ago on slashdot?

    Afraid not, TFA states:

    Is this evidence of a Pliocene love that dare not speak its name? Not according to Reed. He and his colleagues suggest that hominids might have gotten crabs by eating gorilla flesh, perhaps scavenging a carcass. Or they might have slept at nesting sites that gorillas contaminated with their lice. This study just so happens to have come out a few months after another team of scientists showed that [nature.com] chimpanzees not only gave humans HIV but also gave gorillas a related strain of the virus. If chimpanzees can give gorillas a blood-borne virus, it's not too surprising that gorillas could give hominids some lice.
    Anyway, best article linked from /. in ages. Great, thought provoking read.

    I'm going to wonder whether there were savanna gorillas or deep Forest hominids all night now :-)
    • by Alien54 (180860)
      and the creationist crowd says:

      Not only do they say we descended from apes, but we also got their crabs.

      I can see them freaking out on this
    • FTFA: He and his colleagues suggest that hominids might have gotten crabs by eating gorilla flesh, perhaps scavenging a carcass.

            This speculation makes more sense than a hominid might have laid down and slept where a gorilla slept?

            For an internal assimilation such as AIDS I understand, but what's so hard to figure out about this?

        rd
    • Re: (Score:3, Funny)

      by tansey (238786)
      Pretty women out walking with gorillas down my street
      From my window I'm staring while my coffee grows cold
      Look over there! (Where?)
      There's a lady that I used to know
      She's married now, or engaged, or something, so I am told

      Is she really going out with him?
      Is she really gonna take him home tonight?
      Is she really going out with him?
      'Cause if my eyes don't deceive me,
      There's something going wrong around here


      It's amazing how accurate Joe Jackson can be.
    • by Walt Dismal (534799) on Thursday March 08, 2007 @01:24AM (#18272624)
      Ohh. You said 'pubic lice'. I misread the post. I thought you'd said "RIAA". Never mind.
    • We did not get pubic lice from other hominids. We got them from the ancestors of gorillas.

      Well, isn't that what evolution is? Maybe humans and gorillas share a common ancestor. (Well, DUH!)

      I can imagine one of two scenarios:

      1. Humans evolved from the same primates as gorillas, and the lice just stuck with us the whole time.

      2. Some human had sex with a gorilla.

      I just want to know why the christians want to believe number 2 over number 1.

    • by radtea (464814) on Thursday March 08, 2007 @10:12AM (#18275604)
      Anyway, best article linked from /. in ages. Great, thought provoking read.

      It's an excellent article, but the summary makes no sense, which at least encouraged me to read the article to figure out what the hell they were talking about. For example, from the summary:

      The most unsettling result from these studies is that human head lice and human pubic lice (crabs) vary so greatly that they are in two separate genera.

      1) What is "unsettling" about this? Anyone? No prior deeply held beliefs have been overturned. No profound conceptual schemes have been shaken to their very foundations. Parasites are known to be highly specialized. This fact has been published repeatedly for decades, always with great emphasis on how apparently hard it is to believe. After a couple of decades of being routinely reminded that individual species of ticks and fleas and lice are hyper-specialized, do you think we might ask that people stop presenting this fact as something astonishingly new?

      2) The statement is contradicted by the article. What the article says is that head lice and pubic lice in humans are so different morphologically that "early taxonimists" assigned them to different genera. The article implies but does not say explicitly that this early assignment was not in fact justified.

      In any case, this is an absolutely fascinating, albeit tentative and partial, reconstruction of the hominid evolutionary tree from parasite DNA, and I'm sure that as more data from different parasites becomes available we will be in for some real surprises. Internal parasites that are less likely to be passed between species should provide a record that is clearer than the lice record, where despite the relative paucity of inter-species transfers the record has clearly been muddied several times.
      • by T.E.D. (34228)

        The most unsettling result from these studies is that human head lice and human pubic lice (crabs) vary so greatly that they are in two separate genera.

        1) What is "unsettling" about this? Anyone? No prior deeply held beliefs have been overturned.

        There was a point where our human/chimp ancestors were covered with hair like modern chimps. On humans, the hair more or less receded to just our heads and nether regions. At this point, the existing hair-parasites should have started their independent evolutionary

  • hmmmmm (Score:5, Funny)

    by User 956 (568564) on Wednesday March 07, 2007 @11:45PM (#18271946) Homepage
    There were similarities between our pubic lice and the lice found on gorillas.

    Look, I don't know what these scientists have been doing with the gorillas in this study, but this seems like evidence of *something*.
  • by gbulmash (688770) <semi_famous AT yahoo DOT com> on Wednesday March 07, 2007 @11:45PM (#18271952) Homepage Journal
    It's not that humans got crabs from gorillas. One human did. Skeezy McTarzan.
  • Dude... (Score:2, Funny)

    by Starburnt (860851)
    We did not get pubic lice from other hominids. We got them from the ancestors of gorillas." Just.... Dude.
  • hair shape (Score:4, Interesting)

    by mastershake_phd (1050150) on Wednesday March 07, 2007 @11:50PM (#18272000) Homepage
    I heard somewhere and I believe it to be true that African Americans hair has a oval shape instead of round. For this reason the lice cant grab on, and they don't have lice problems.
    • That's not true: read this article [findarticles.com]. It's rare but not impossible, and more common in other countries.
      • Its true, from the article you listed: studies have found that up to 25% of white children have had head lice, compared to less than 1% of African American children

        African American hair is more elliptical than white children's hair and head lice find it difficult to hold onto elliptical hair
        • Re:hair shape (Score:4, Informative)

          by Arker (91948) on Thursday March 08, 2007 @03:38AM (#18273344) Homepage Journal
          It all goes back to the very tight coupling between parasite and host. Even tiny differences between different populations in a host species are mirrored in parasite populations. So lice populations found among hosts of European ancestry have a difficult time with African hair forms. African lice populations, however, do not. Apparently lice populations in North America are mostly of European derivation, but that is far from true in other areas.
    • Not specifically "African" hair but curly hair in general. If it's curly, the cross-section is more oval than circular.
  • by lawpoop (604919) on Wednesday March 07, 2007 @11:51PM (#18272014) Homepage Journal
    I remember something from my days of getting an anthropology degree where some scientists was trying to guess the approximate date when humans first started wearing clothing. Tools made from bone and rock last a long time, so you can easily get a good idea of when people started making new types of tools. But stuff like clothing, rope, or weaving rots away pretty quickly, so finding them in archaeological digs is pretty rare.

    IIRC, there are two types of lice or fleas. One kind lived on human skin and hair, and the other preferred clothing and blankets and lived only in artificial fabrics. The scientists were trying to see when the fabric-preferring bugs diverged from a common ancestor by examining the genetics. Really clever!
    • by tomhudson (43916)

      "One kind lived on human skin and hair, and the other preferred clothing and blankets and lived only in artificial fabrics. "

      That's why you should never buy that tacky polyester K-Mart sh*t. Get natural fabrics.

      • by QuantumG (50515) *
        All fabrics are artificial.. I don't think I've ever seen a blanket or a shirt tree.

        Kinda reminds me of people who complain about fruit having "chemicals" in them.
        • Re: (Score:3, Funny)

          by tomhudson (43916)

          "All fabrics are artificial.. I don't think I've ever seen a blanket or a shirt tree."

          You're confusing the thing with what its made of. While there aren't "blanket trees," there certainly ARE cotton plants, and wool occurs naturally as well - ask any sheep. So you can make blankets and clothing out of cotton, or wool, or any other naturally-occuring fibre - but you won't find any naturally-occuring polyester. And don't get me started on how many naugas you have to kill to get even one decent naugahide

          • O.K. if you take the WoW perspective on that it takes 300 Nagas to get 1 Naga Claw. When you get thirty claws, you take them to the elder in Sha laka ah, and he gives you a quest to get 10 Naga Hides. The drop rate for Naga hides is about 1 in 1000, but they come quick if you drop a skill and trade up skinning!
    • by zappepcs (820751) on Thursday March 08, 2007 @12:30AM (#18272268) Journal
      This is really interesting. There are other things where we know what the change was, and when it happened that might affect evolution in some species. I wonder if anyone is studying them.

      My thoughts: The widespread use of DDT is a known event that had wide ranging affects on the environment. Are there evident evolutionary effects on insects?
      Does anyone study what the common cold looks like after many attempts to inoculate us against it?

      I wonder if there are defined evolutionary differences in any species after the plagues?

      Interestingly, we apparently don't even know if the food we eat today has the same nutritional value of the food that humans were eating 100 years ago.

      Very interesting.
      • by PCM2 (4486)

        Does anyone study what the common cold looks like after many attempts to inoculate us against it?

        IANAS, but I would hazard the answer to this is "yes," but that the results are inconclusive. The whole problem with the common cold, what makes it so difficult to inoculate against, is that it routinely "looks like" so many different things that we can't come up with a vaccine that will "recognize" them all.

      • Re: (Score:2, Interesting)

        by eheldreth (751767)

        I wonder if there are defined evolutionary differences in any species after the plagues?

        Actually, I read an interesting article a while back that descendants of the black plague have a mutation that gives them some immunity to HIV.
        Here is a random article from Google [pbs.org]
    • Re: (Score:2, Interesting)

      by rez_rat (1618)
      So why do all those cavemen (cavewomen?) women wear bras, and men don't?

      Seriously... in the study of ancient clothing... was it really that important for a woman to cover up her upper parts?? On the other hand (hehe), was this just something we devised later on? :-P

      Sounds stupid, but, ... I'm curious.

      S-
    • Gorilla skins are probably the best "off the rack" fit nature provides, let's face it - Chimpas are too small and the sleaves on an Oragutang are way too long.

      Seriously though, INA-Anthorpologist but I would have thought that prototype clothing was made from animal skins? Early Europeans are known to have used whale skins to make portable huts and what little is left of tribal cultures today still wear animal skins or plated leaves.

      TFA - Another thing to take into consideration is that tribal people h
    • The clothing dating you are referring to was actually also featured on Slashdot [slashdot.org] under the Best /. Headline Ever: Pants Were Optional, 100,000 Years Ago.

      That paper, with its abstract available from PubMed [nih.gov], was from Mark Stoneking's group and I believe they said in interviews that they intended to pursue studying the difference between head lice and pubic lice to figure out when we lost our fur. So maybe this result tells us why there was no follow-up paper: The data could not be used to address that issu

    • by 1u3hr (530656)
      IIRC, there are two types of lice or fleas. One kind lived on human skin and hair, and the other preferred clothing

      RTFA. There are three types: Head, pubic, clothing.

      • by lawpoop (604919)
        I was indicating that I didn't remember if the research was centered around fleas or lice.
        • by 1u3hr (530656)
          Or in other words, you didn't RTFA.
          • by lawpoop (604919)
            I was referring to another article about other research. RTFC.
            • by 1u3hr (530656)
              I was referring to another article about other research. RTFC.

              These other researchers must have been pretty clueless then. Or you didn't actually read that either.

    • by argStyopa (232550)
      The keys being:
      - head lice and body lice have entirely different grasping systems. Non-interchangeable.
      - lice can't survive IIRC more than a few hours away from a host. So their lifespan is intimately connected with their host(s)
      - lice are species specific

      Human body lice therefore are unlikely to have evolved their grasping mechanism (useless with body hair or wearing animal skins/furs) until shortly after textiles would have become common clothing for humans. So it doesn't give us precisely when humans
    • Actually, there's a Slashdot article on this very subject. I know, because I submitted it!

      Pants Were Optional, 100,000 Years Ago [slashdot.org]
      Posted by timothy on Tue Aug 19, '03 08:48 PM
      from the lousy-research-methods dept.
      RobertB-DC writes
      "German scientists have used differences in the DNA of lice to determine when humans started wearing clothes. It seems lice are highly specialized -- head lice lay their eggs only on hair, while body lice hide theirs in the folds of clothing. Using the differences in the two species'
  • Hate to be the naysayer of the group, but this seems pretty speculative to me. The connection between the gorilla strain of lice and the human head lice is an interesting observation, but that doesn't necessarily mean all that was claimed. I'm not dismissing the theory, but there is not enough evidence to sell me on this one. Does the premise sound good? Yes, but that is hardly enough to justify the evolutionary links between lice and the various branches of primates.
  • by Daniel Dvorkin (106857) * on Thursday March 08, 2007 @12:05AM (#18272118) Homepage Journal
    To be perfectly honest ... um, let me think about this ... no.
  • Huh huh. You said.. "pocket gopher".
    • I hate to admit it, but that was the first thought I had, too.

      "Is that a gopher in your pocket or are you just glad to see me?"
  • Where is the link to Lawyers ?? I would have thought that all parasites were geneticaly related?
  • by jpellino (202698) on Thursday March 08, 2007 @12:41AM (#18272344)
    "We did not get pubic lice from other hominids. We got them from the ancestors of gorillas."

    #10. Speak for yourself, professor.

    #9. "coyote-ugly", move over...

    #8. Shhh... Hear that? I think Dave Attell's head just exploded.

    #7. Why is the waiting room empty? All I said was we...

    #6. "Scratch-a while you can, monkey-boy!"

    #5. Next on Springer...

    #4. Time to bring the crab-infested brass monkeys in off the back porch, Radar.

    #3. Yes, you heard me right, I need to get into those crabs' genes.

    #2. Let's say we ask Jocelyn Elders to weigh in on this one.

    and #1... Well I'll be a monkey's uncle, and a mighty itchy one at that.

    (N.B., I know gorillas are apes not monkeys, so save the posting effort, it's just a freaking joke...)

    • by catbutt (469582)

      (N.B., I know gorillas are apes not monkeys, so save the posting effort, it's just a freaking joke...)
      Well, since that part doesn't appear to be a joke, I'll address it. Apes are really monkeys, if monkeys are to be considered a monophyletic group. Apes are within the old world monkey clade. And yes, we ARE evolved from monkeys, despite what many well meaning people defending Darwinism will tell you.
      • by Zenaku (821866)
        I like phylogenetic (or cladistic) taxonomy as much as the next guy, but if you're going to make a statement like this you should at least acknowledge that you are using a different (and much newer) system of classification than the person you are "correcting."

        Personally, I think phylogenetic taxonomy makes a hell of a lot more sense -- but we all learned alpha taxonomy in school, and that's very clearly what all those well meaning people are using.

        Spouting off about how everybody has it all wrong without p
        • by catbutt (469582)
          There are direct ancestors of humans that, by any taxonomic classification system, were monkeys. Just a species of monkey that isn't alive today, but a monkey nonetheless.
  • by doubletruncation (939847) on Thursday March 08, 2007 @12:52AM (#18272414)
    From the article: "And then there is the matter of where the lice live. Today, lice live on little islands of hair on an ocean of hairless human skin. They are clearly adapted to our relatively hairless bodies. The authors suggest that their results may mean that hominids were already losing hair 3.3 million years ago. The gorilla lice needed an empty ecological niche--pubic hair--that they could occupy in order to survive. If hominids had full-body hair, the lice that already lived on it might have been able to outcompete an invader."

    In my opinion this is one of the most interesting aspects of this research - being able to date when we started becoming hairless. It's always been a puzzle why we are relatively hairless compared to the other great apes, and I would guess that being able to put some time constraints on it is a step toward understanding how this happened.
    • by catbutt (469582)
      Well I don't see that it is THAT much of a puzzle as to why. I assume it is related to the invention of clothing. Clothes have a lot of advantages over fur, such as the ability to toss em in the fire when they get full of lice, to dry them when wet, to take them off when its hot, and put more on when cold. So once we had that, fur became a liability.
    • by gobbo (567674)

      In my opinion this is one of the most interesting aspects of this research - being able to date when we started becoming hairless. It's always been a puzzle why we are relatively hairless compared to the other great apes, and I would guess that being able to put some time constraints on it is a step toward understanding how this happened.

      And how about that head-hair, eh? In most straight-haired people, it grows to indeterminate length, until it gets cut or strangles its bearer. Where's the evolutionary advantage of that? What a weird design. I wonder if it's a product of culture working through evolution: the the need for hair grooming is part of the social pact, keeps us in the troupe. A deep syntax of the body?

      Maybe head lice elicited the long, straight round hair in our genome. They certainly are specialized, can't survive anywhere el

      • by dzimmerm (131384)
        Hair lasts between 2 to 6 years. Hair grows at about 1/4 inch to 1/2 inch a month. This does result in a terminal hair length. Hair is not forever.

        dzimmerm
        • by gobbo (567674)

          Hair lasts between 2 to 6 years. Hair grows at about 1/4 inch to 1/2 inch a month. This does result in a terminal hair length. Hair is not forever.

          Granted, I was exaggerating. Only a few people manage hair longer than their body. Many millions, however, have hair past their butt. Terminal hair length is potentially very long.

          It still seems even more absurd to me than extreme sexual signalling like the tail feathers of Birds of Paradise.

      • by jafiwam (310805)
        Hair and hair growth is a secondary sexual characteristic that is used by the opposite sex to determine breeding fitness.

        Chicks with nice hair (listen to them talk amongst themselves sometime you might learn something) have proven they can be healthy enough for the 3 year marathon of having a kid. So the hair makes men want to screw them, and makes other women aware men want to screw the nice hair ones.

        Why do you think the butch dykes cut their hair like Rosie ODonell? To remove the "I am a good breeder"
        • by gobbo (567674)

          Chicks with nice hair (listen to them talk amongst themselves sometime you might learn something)

          Ah, you presumptuous, arrogant, snide little whippersnapper! Since it's humourous flamebait, I'll let it slide this time.

          You're paraphrasing the dominant theories. I'm not unaware of them, and I don't disagree with them, but I don't trust them entirely either. The runaway sexual selection this idea relies on doesn't adress all ethnicities (e.g. the !Kung keep short hair, and it's wiry enough that they can just break it off), and there's the possibility that it signifies youth in an exaggerated manner (ne

      • by TheLink (130905)
        "Where's the evolutionary advantage of that?"

        How about: coz enough people thought it looked nice AND the minuses aren't significant enough to select against it.

        Evolution isn't about optimums - it's all about good enough. As long as it reproduces it doesn't matter how silly it looks or behaves or whatever.

        You see tons of ridiculous creatures teetering at the edge of survival all the time, especially in places where energy and other resources are abundant.

        And even in places where resources are not as abundant
        • by gobbo (567674)

          ...head hair is good for preventing sun burn on our heads.

          I'm bald, you insensitive clod!

          Sorry, couldn't resist. Anyway, my question about evolutionary advantage was mostly rhetorical. I was trying to make the point that our natural selection is directed by culture and technology (another one is the shape of our jaw: cooking has made it weak and smaller), and I wonder if in fact the lice themselves haven't had more evolutionary effect than we suspect on the kind of hair we grow on our heads (i.e. less elliptical, longer).

    • Re: (Score:3, Interesting)

      by dzimmerm (131384)
      My understanding was that sweating for cooling as we do is more efficient with less hair. Humans are designed to run long distances at a fairly high rate of speed. Many animals are faster in the short haul but humans can out run any creature on earth in the long haul. That running required better heat dissipation and so we lost our hair and sweated more.

      Clothing and hair loss are not really related. Clothing and moving to to temperate and arctic climates are probably much more related.

      dzimmerm
      • Re: (Score:2, Informative)

        by Anonymous Coward
        Many animals are faster in the short haul but humans can out run any creature on earth in the long haul.

        I think horses can usually outrun humans even for long distances. See also: Man versus Horse Marathon [wikipedia.org]
        • Not sure about that (Score:3, Interesting)

          by spineboy (22918)
          Indigenous American Indians used to catch horses by outrunning them, until the horse was too tired to run anymore. If one trains a horse to run long distances, then I don't know, but a typical wild horse is not much of a match against a determined, trained human in terms of distance.
          So I guess both the parent and grandparent messages are correct.
    • "The gorilla lice needed an empty ecological niche--pubic hair--that they could occupy in order to survive. If hominids had full-body hair, the lice that already lived on it might have been able to outcompete an invader."

      Someone jump in and tell me how this could possibly happen. We lost our body hair, but not our crotch, underarm or head hair. So the lice we were carrying before losing that hair...

      A. Hated our pubic reagions and head.
      B. were unable to adapt to
  • by benow (671946) on Thursday March 08, 2007 @01:01AM (#18272474) Homepage Journal
    think twice about who you share your brain bucket with.
  • by Anonymous Coward
    The coevolution of parasites and their hosts is admirably exemplified by the hordes of clueness do-nothing know-nothings who rush to offer hilariously foolish comments on slashdot.
  • by GrumpySimon (707671) <email.simon@net@nz> on Thursday March 08, 2007 @01:59AM (#18272878) Homepage
    Rather than read a second-hand account (although Carl Zimmer is very good), the original article is open access and is available here: http://www.biomedcentral.com/1741-7007/5/7/abstrac t [biomedcentral.com]

    Conclusion:

    Reconciliation analysis determines that there are two alternative explanations that account for the current distribution of anthropoid primate lice. The more parsimonious of the two solutions suggests that a Pthirus species switched from gorillas to humans. This analysis assumes that the divergence between Pediculus and Pthirus was contemporaneous with the split (i.e., a node of cospeciation) between gorillas and the lineage leading to chimpanzees and humans. Divergence date estimates, however, show that the nodes in the host and parasite trees are not contemporaneous. Rather, the shared coevolutionary history of the anthropoid primates and their lice contains a mixture of evolutionary events including cospeciation, parasite duplication, parasite extinction, and host switching. Based on these data, the coevolutionary history of primates and their lice has been anything but parsimonious.
  • Just conducting a little more "research"...

    http://www.lessonsforhope.org/images/cartoon_larso n.gif [lessonsforhope.org]


  • Help Jodie Foster get RID of them!
  • When my SO wonders where the crabs came from, I can mumble, "Ah, fucking gorillas."
  • Not only am I a monkey's uncle, I got his crabs too!
  • We did not get pubic lice from other hominids. We got them from the ancestors of gorillas.

    Hey, mister, speak for yourself!!!

  • Flied lice (Score:3, Funny)

    by metamatic (202216) on Thursday March 08, 2007 @11:33AM (#18276578) Homepage Journal

    There were similarities between our pubic lice and the lice found on gorillas.

    What do you mean "our pubic lice"?

    This is Slashdot, most of us haven't had the opportunity to get public lice, you insensitive clod!

  • "We did not get pubic lice from other hominids. We got them from the ancestors of gorillas."

    Where does Paris Hilton get hers?

    Based on some of her sex vids, I gotta say maybe from the same source, since many of her boyfriends appear to be gorillas - or at least dumber than gorillas.

    Maybe even dumber than her, since they're screwing her.

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