Follow by Email

Thursday, April 22, 2010

Lice hang ancient date on first clothes Genetic analysis puts origin at 190,000 years ago

Lice hang ancient date on first clothes
Genetic analysis puts origin at 190,000 years ago
By Bruce Bower
Web edition : Tuesday, April 20th, 2010


Buggy dudsA genetic analysis of head and body lice suggests that
people may have begun making and wearing clothing as early as 190,000
years ago.Janice Harney Carr, Center for Disease Control


ALBUQUERQUE — For once lice are nice, at least for scientists
investigating the origins of garments.


Using DNA to trace the evolutionary split between head and body lice,
researchers conclude that body lice first came on the scene
approximately 190,000 years ago. And that shift, the scientists
propose, followed soon after people first began wearing clothing.


The new estimate, presented April 16 at the American Association of
Physical Anthropologists annual meeting, sheds light on a poorly
understood cultural development that allowed people to settle in
northern, cold regions, said Andrew Kitchen of Pennsylvania State
University in University Park. Armed with little direct evidence,
scientists had previously estimated that clothing originated anywhere
from around 1 million to 40,000 years ago.


An earlier analysis of mitochondrial DNA from the two modern types of
lice indicated that body lice evolved from head lice only about 70,000
years ago. Because body lice thrive in the folds of clothing, they
likely appeared not long after clothes were invented, many scientists
believe.


Though well suited to gauging the timing of evolutionary events,
mitochondrial DNA is a relatively small part of the genome. Kitchen’s
team examined both mitochondrial and nuclear DNA samples from head and
body lice, yielding the much older, and presumably more accurate,
estimate of when body lice first evolved.


It makes sense that people, or perhaps Neandertals inhabiting cold
parts of Europe, started making clothes around 190,000 years ago,
Kitchen explained, since both species had already lost most body hair
and knew how to make stone tools for scraping animal hides. Homo
sapiens originated approximately 200,000 years ago.


The researchers calculated relatively fast mutation rates for both
forms of lice, so the new age estimate for the divergence of body lice
from head lice is a conservative one. It’s possible for body lice to
have evolved from head lice in only a few generations, according to
laboratory studies, Kitchen said. No evidence indicates that head lice
can evolve from body lice.
Source
Share/Bookmark

No comments: