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

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

[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

[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

[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

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

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.