Abstract/Summary

Over the past few decades there has been an increased demand for genome analysis of ancient human remains. Destructive sampling is increasingly difficult for ethical reasons, and previous methods of breaking the skull to access the petrous bone are often forbidden for curatorial reasons, together with teeth which may be missing or too precious to sample. However, most ancient humans carried head lice, and their eggs abound in historical hair specimens. Here we show that host DNA is protected by the cement that glues head lice eggs (nits) to the hair of ancient Argentinian mummies, 1,500–2,000 years old. The cement also preserves ancient environmental DNA of the skin, including the earliest recorded case of Merkel Cell Polyomavirus. We also show that human DNA obtained from nit cement can equal human genome assessment from tooth DNA, can increase assessment from petrous bone by two-fold, and by four-fold DNA over bloodmeal of adult lice a millennium younger. Genome-wide analyses from nit cement DNA also enables identification of the population genetic affinities of ancient humans. In metric studies of the sheaths, the length of the cement tube negatively correlated with the age of the specimens, while hair linear distance between nit and scalp informed about environmental conditions at the time before death. Ectoparasitic lice sheaths on hair, feathers, skins, or mummified remains can offer an alternative, non-destructive source of high-quality ancient DNA from a variety of host taxa and reveal details of their historical environment.