Putting on clothing to protect our woefully hair-deficient bodies is one of the key moments in the history of becoming human. Just when our species took this step, however, is open to a fair amount of guesswork—scientists can’t exactly dig up fossilized parkas and trousers. But what scientists can do is determine roughly when two species diverged, and that has made all the difference: Using the lice that have traveled with people for thousands of years, a team has tracked the time that humans first became dedicated followers of fashion—perhaps as long as 170,000 years ago.
Very nice work (and you can look at the whole paper) based on a cool idea – when did head lice and body lice diverge. Since body lice require clothing for survival, this might give us some information regarding when we started to use clothing.
The dates have a large range, between 83,000 and 170,000 years ago, probably due to the fact that only four genes were looked at. This fits very well into the need for Ice Age protection and also with the Out of Africa time line.
But the really cool thing is that this work was done by using what was already in public databases. That means that actually anyone could have done a similar analysis. Of course, you would have to know the ‘right’ way to do this and be comfortable throwing around phrases like “Bayesian coalescent modeling approach” but even the programs they used for analysis were ones available for use.
They very smartly used databases to mine for information based on a hypothesis they had. No new experiments were needed.
So, in one sense, this work could have been done by anyone from home. It requires insight and deep understanding and maybe access to the right programs but it is not something that would require a huge research grant and lots of expensive equipment.
Of course, I would expect that if you had been doing this work based on a PC at home, you’s still be watching it run the Markov simulations. You might be able to do this at home but having access to fast computers is a large plus.
And now, we need to have the genomes of each species completely sequenced in order to narrow down the time range. We have done that for the body louse. It has the smallest genome of any insect – only 108 million bases pairs of DNA (for comparison, the human genome has about 3 billion base pairs). Let’s get the head louse – and perhaps the pubic ouse for good measure.