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"Lousy" study shows clothing 70,000 years old
By Maggie Fox, Health and Science Correspondent
WASHINGTON, Aug 18 (Reuters) - Adam and Eve may have put on
fig leaves while still in the Garden of Eden but a study that looked at the
most intimate of pests -- body lice -- suggests that humans started wearing
clothes 70,000 years ago, scientists said on Monday.
The genetic study of the lice strongly suggests they -- and
clothing -- arose soon after modern Homo sapiens began moving out of Africa and
into the cooler regions of Europe.
Lice provide a unique insight into the development of
clothing, according to the researchers, working in Germany. Only humans carry
this particular species of louse, which lays its eggs in clothing and spreads
typhus, among other diseases.
"It seems fairly obvious that the body louse arose when
humans made frequent use of clothing," molecular anthropologist Mark
Stoneking said in a telephone interview.
Stoneking and colleagues Ralf Kittler and Manfred Kayser,
all of the Max Planck Institute for Evolutionary Anthropology in Leipzig,
Germany, report their findings in this week's issue of the journal Current
Biology.
Experts are eager to know when people first started to wear
clothes. But while stones, tools and other evidence of human behavior survive
for millennia, clothing does not.
WARNINGS ABOUT COOTIES
Stoneking, an American, thought of a way to figure it out
when his son came home from school with a teacher's note.
"It was one of those notices where they let parents
know some kid in the classroom has come down with head lice," Stoneking
said.
"One of the points it made was that you only get head
lice from other humans ... you can't get them from your dog, your cat, etc. And
lice cannot survive more than 24 hours away from the human body," he
added.
"It occurred to me then that if that is really true,
that the spread of human lice around the world would have been driven by
humans."
Three species of louse infect humans -- head lice, known to
generations as "cooties", body lice and pubic lice or
"crabs". Experts agree body lice are a subspecies of head lice and
that body lice probably evolved when people started to wear clothing.
Stoneking's team used a molecular clock to find out when
body lice evolved.
They looked at the DNA found in the mitochondria of cells.
This DNA is inherited virtually intact from the mother, with any changes
happening through mutation alone.
The rate of mutation can be calculated, with a certain
number of changes expected with each generation. By comparing the mitochondrial
DNA of body lice to that of a cousin -- chimpanzee lice -- the researchers were
able to date it back to around 70,000 years ago.
This, Stoneking said, fits in with growing evidence that
modern humans evolved in Africa and migrated out around 100,000 years ago. A
comparison of body lice from around the world shows their genetic diversity
mirrors that of humans, as well, also supporting the idea that they evolved in
Africa first.
As with people, lice found in different parts of Africa are
more different from one another genetically than an African louse versus a
European louse, for example.
Stoneking is now starting to look at pubic lice, or crabs.
He at first believed they might shed light on when humans lost their heavy body
hair.
"But I found out that entomologists and taxonomists
pretty much are united in agreeing that human pubic lice are more related to
gorilla lice than to head lice. I don't want to speculate on what our ancestors
were up to to get gorilla lice in the pubic area," Stoneking said.
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Posted August 20, 2003