The Coevolution of Lice & Their Hosts

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."

Comments

Gorilla / Human lovin'?

[Whiney Mac Fanboy]

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 (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 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 :-)

Re:Gorilla / Human lovin'?

[tansey]

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.

Re:Gorilla / Human lovin'?

[Walt Dismal]

Ohh. You said 'pubic lice'. I misread the post. I thought you'd said "RIAA". Never mind.

Re:Gorilla / Human lovin'?

[radtea]

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.

hmmmmm

[User 956]

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*.

Not humans... a human.

[gbulmash]

It's not that humans got crabs from gorillas. One human did. Skeezy McTarzan.

Dude...

[Starburnt]

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

hair shape

[mastershake_phd]

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.

Re:hair shape

[mastershake_phd]

"In Africa, where the percentage of children with head lice is higher, lice have adapted their claws to better grasp elliptical hair"

It looks like its an arms race then.

Re:hair shape

[Xonstantine]

It looks like its an arms race then.

That's exactly what parasite-host relationships are. Evolution isn't so much a march in a straight line, but a vicious cycle of decimation-immunization-regression to naivete-back to decimation, ie, the Red Queen hypothesis. The really interesting thing is the degree to which parasites have affected evolution. A lot of secondary sex characteristics, because of their biological expense, are really good indicators of parasite resistance.

Re:hair shape

[rez_rat]

JUST LIKE a Slashdot'ian to look down at the wierd things in his bush... and try to EXPLAIN them!!

I can't help it: "Just imagine a Beowolf cluster of these!!!"

haha

S-

Re:hair shape

[Arker]

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.

Re:hair shape

[inviolet]

It sounds like these kids get a break for being a minority in this case. In the US where African ancestry puts you in the minority, there might not be a big enough survival advantage for the necessary mutation to dominate the louse population. Even though there are pockets of the US where African ancestry is in the majority, the mutation may not have taken hold yet. If true, this might indicate that it takes a while for lice to evolve this feature. To really answer that question though, we should do a comparison in school districts where African ancestry is in the majority, and has been for quite some time.

One confounding factor in this issue is the fact that WASPs can also have elliptical hair. That's what "naturally curly" hair is. African hair is curly for the same reason, albeit more so.

Dating the first clothing

[lawpoop]

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!

Re:Dating the first clothing

[zappepcs]

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.

Re:Dating the first clothing

[tomhudson]

"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.

Re:Dating the first clothing

[rez_rat]

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-

Re:Dating the first clothing

[hazem]

Ever try cooking bacon naked? THAT's why we have clothes.

Re:Dating the first clothing

[eheldreth]

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

"Ever wonder if pocket gophers have lice?"

[Daniel Dvorkin]

To be perfectly honest ... um, let me think about this ... no.

Re:"Ever wonder if pocket gophers have lice?"

[dnc253]

Are you kidding me?! This question has been plaguing me for weeks! Thank goodness I now know the answer so I can finally get some sleep!

Re:"Ever wonder if pocket gophers have lice?"

[Frogbert]

Further to that...

What the fuck is a pocket gopher?

Re:"Ever wonder if pocket gophers have lice?"

[modecx]

My pocket gopher had lice once. It was very irritated.

So many responses, so little time...

[jpellino]

"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...)

Timing when we lost our hair

[doubletruncation]

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.

Re:Timing when we lost our hair

[dzimmerm]

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:Timing when we lost our hair

[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

lice story after brain game controller...

[benow]

think twice about who you share your brain bucket with.

We can see it right here on /.

[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.

Re:Evidence of Intelligent Design

[Tablizer]

The all powerful one is known to be against that nasty bahaviour known as "s*x" (except when used to go forth and multiply of course). He produced pubic lice as a punishment for those engaging in this disgusting activity.

We can test this. Have gay sex with a dirty ape while gambling, drinking, and cussing and see if you get struck by lighting and hurricanes more often then those having Brady-Bunch-Mormon-style relationships.

Re:The REAL Question of the Day!!...

[rez_rat]

Oh,... and this is NOT a "In Soviet Russia" joke. :-P

Rather than read a second-hand account...

[GrumpySimon]

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

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.

Re:another incorect assumption

[mr_3ntropy]

Sigh. Another sheep argument with Irreducible Complexity. None of the candidates for this kind of "Gap" theology have stood up to scientific analysis. Other sheep have argued in a similar manner about the eye, the flagella, etc.

I wish Richard Dawkins was made required reading for all the misguided lambs every Saturday night before churchday.

Hand in there my friend, there is still hope. You can be saved.

Re:another incorect assumption

[truckaxle]

Uhhhh I think not.

That was the only thing you said that made sense ;)

Not sure about that

[spineboy]

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.

Flied lice

[metamatic]

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!