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Head Lice Provide Best Ever Human DNA Extracted From Mummies

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Rachael Funnell

Digital Content Producer

clockDec 28 2021, 21:00 UTC
head lice cement human DNA

You could one day be identified by the nit goo in your hair. Image credit: Universidad Nacional de San Juan

Jurassic Park chose mosquito fossils as the harborers of Dino DNA, but a different kind of parasite recently came to the rescue in preserving the genetic material of ancient humans yielding samples of unprecedented quality. Trapped within the "cement" head lice use to secure their eggs, researchers found DNA in the hair of mummified remains from Argentina that date back to 1,500-2,000 years ago. What’s more, the novel technique for acquiring ancient human DNA actually works better than previously used methods and allows us to sample human remains in a way that's less invasive.

The head lice, also known as “nits”, were able to trap human DNA as skin cells from the host’s scalp got encased in the cement-like substances that female eggs produce. They create a setting glue so that they can secure their eggs in hair close to the head where it's warmest. Not so fun for the host but something of an Easter Egg for molecular biologists and evolutionary scientists, clearly.

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According to the study, published in Molecular Biology and Evolution, this is the first time such DNA has been acquired in this way, providing a new way of looking into the genes of humanity’s past. Its authors claim the information has already provided fresh clues about pre-Columbian human migration patterns within South America and could provide a new way of analyzing specimens that don’t have teeth or bones to sample.

Head lice: don't knock 'em until you've tried extracting ancient human DNA from 'em. Image credit: University of Reading

“Like the fictional story of mosquitos encased in amber in the film Jurassic Park, carrying the DNA of the dinosaur host, we have shown that our genetic information can be preserved by the sticky substance produced by head lice on our hair,” said lead researcher Dr Alejandra Perotti, Associate Professor in Invertebrate Biology at the University of Reading, in a statement.

Before now, dense skull bone or the inner material of teeth was needed to get quality genetic material. Unfortunately, these are both quite destructive means of acquiring DNA and so aren’t always culturally or ethically appropriate when dealing with human remains.

Another look at that skin-flake-laced nit cement. Image credit: University of Reading

“Demand for DNA samples from ancient human remains has grown in recent years as we seek to understand migration and diversity in ancient human populations," continued Perotti. "Head lice have accompanied humans throughout their entire existence, so this new method could open the door to a goldmine of information about our ancestors, while preserving unique specimens.”

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The samples acquired using nit cement were found to contain the same amount of DNA as a tooth sample, double the amount yielded from bone samples and four times the amount in the blood found in the stomachs of more recent lice remains. All that juicy genetic information without the need to break bones? The solution was hiding in our heads all along.

Speaking of less invasive ways of studying mummified remains, check out this Egyptian mummy being "digitally unwrapped" after 3,000 years.


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