There is a wealth of information hidden in the ‘glue’ that the lice used thousands of years ago to attach their eggs to the hairs of these mummies.

Head lice are an all-time problem. Head lice have been found both in mummies from Egypt and in excavations of thousands of years old Viking settlements in Greenland. However persistent these critters may be, they also have a particularly favorable side. Because head lice appear to harbor a gold mine of information about long-dead people.


Researchers have discovered that human DNA can be extracted from the ‘glue’ that lice used thousands of years ago to attach their eggs to hair. A special discovery. Until now, ancient DNA was extracted from skull bone or from teeth. However, such human remains are not always available. In some cases, it is unethical or against cultural beliefs to take samples of human remains. In other cases, taking samples can further damage the already fragile remains. Recovering DNA from glue released by lice is therefore a promising solution. Especially since nits are often found on the hair and clothing of well-preserved mummies.


In a new study To the test, researchers took a look at the hairs of mummified human remains dating back between 1,500 and 2,000 years. The team subsequently managed to extract human DNA from the glue that the lice used thousands of years ago to attach their eggs to the hairs of these mummies.

A human hair with a lice egg attached to it, attached with the help of ‘glue’. Image: University of Reading


How this works Female lice produce glue when they attach their eggs – known as nits – to the hair. However, during this process, skin cells from the scalp are also encapsulated in the adhesive. “We have shown that our genetic information can be preserved by the sticky substance produced by head lice on our hair,” said study researcher Alejandra Perotti.

This photo shows a louse nit with the glue covering the eggshell and hair shaft. The thick arrow points to a human cell. Image: University of Reading

In this way, ancient DNA is effectively preserved. In fact, the samples studied in the study were found to contain the same concentration of DNA as a tooth and even twice as much as bone remains, the researchers show. “These high amounts surprised us,” said researcher Mikkel Winther. “We even managed to decipher exactly who these people were.”


By analyzing the ‘lice glue’, the researchers were able to uncover some interesting secrets about the mummies studied. For example, they managed to determine the sex of each of the examined mummies. In addition, they found a genetic link between three of the mummies and humans who inhabited the Amazon region 2,000 years ago. This shows for the first time that the original population of the Argentine province of San Juan migrated from the Amazon forest to the north of the continent.

cause of death

In addition, the researchers determined the cause of death of the examined mummies. For example, they were probably all exposed to extreme cold when they died. How do the researchers know? The team found a very small gap between the nits and the scalp. Lice depend on the warmth of their host’s head to keep the eggs warm. And so, when the temperatures are low, female lice lay their nits closer to the scalp.

All in all, the nits found on the ancient mummies shed new light on their past. An important step. Because possibly future information can provide more valuable clues about how people lived and died thousands of years ago. “The demand for DNA samples from ancient human remains has grown in recent years,” Perotti said. “That’s because we’re trying to understand the migration and diversity of ancient human populations. Head lice have accompanied humans their entire existence. So this new method could open the door to a goldmine of information about our ancestors, while leaving the unique specimens untouched.”