Abstract
Over the past few decades, there has been a growing demand for genome analysis of ancient human remains. Destructive sampling is increasingly difficult to obtain for ethical reasons, and standard methods of breaking the skull to access the petrous bone or sampling remaining teeth are often forbidden for curatorial reasons. 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 nits to the hair of ancient Argentinian mummies, 1,500–2,000 years old. The genetic affinities deciphered from genome-wide analyses of this DNA inform that this population migrated from north-west Amazonia to the Andes of central-west Argentina; a result confirmed using the mitochondria of the host lice. The cement preserves ancient environmental DNA of the skin, including the earliest recorded case of Merkel cell polyomavirus. We found that the percentage of human DNA obtained from nit cement equals human DNA obtained from the tooth, yield 2-fold compared with a petrous bone, and 4-fold to a bloodmeal of adult lice a millennium younger. In metric studies of sheaths, the length of the cement negatively correlates with the age of the specimens, whereas hair linear distance between nit and scalp informs about the environmental conditions at the time before death. Ectoparasitic lice sheaths can offer an alternative, nondestructive source of high-quality ancient DNA from a variety of host taxa where bones and teeth are not available and reveal complementary details of their history.
Highlights
Over the last 30 years, ancient DNA has proven to be a key source of information about past organism assemblages, diversity and evolution
We found that the percentage of human DNA obtained from nit cement equals human DNA obtained from the tooth, yield two-fold compared to a petrous bone, and four-fold to a bloodmeal of adult lice a millennium younger
ADNA has been obtained from a variety of materials including bones and teeth (Poinar et al 2006; Shapiro and Hofreiter 2012; Feldman et al 2016; Massilani et al 2020; Curry et al 2021; Woods et al 2021), bird toe pads (Shapiro and Hofreiter 2012), coprolites (Hofreiter et al 2000), keratin and chitin (Shapiro and Hofreiter 2012; Gazda et al 2020), eggshells (Shapiro and Hofreiter 2012), chewed birch pitch (Jensen et al 2019) and sediments (Shapiro and Hofreiter 2012; Slon et al 2017; Rohland et al 2018; Zhang et al 2020) from archaeological sites, geological settings and museum collections
Summary
Over the last 30 years, ancient DNA (aDNA) has proven to be a key source of information about past organism assemblages, diversity and evolution. Extracting DNA from these materials is destructive and often results in irreparable damage to unique archaeological specimens and in addition, depletes the sample for future physical, biological and taphonomic analyses (Geigl and Grange 2018; Ponce de Leon et al 2018; Prendergast and Sawchuk 2018; Palsdottir et al 2019; Sirak et al 2020). There is a demand for alternative, non-destructive procedures to the current methods and to explore other material sources such as dental calculus, a source of host and/or microbial and dietary DNA (Warinner et al 2014; Ozga et al 2016; Nieves-Colón et al 2020) Another underexploited, non-invasive source are parasites, as they often contain and preserve ancient host DNA. They hold the potential to inform about past dispersal and host interactions but unravel host health conditions and even the cause of death of individuals (Panagiotakopulu et al 2007; Dittmar 2009; Panagiotakopulu et al 2013; Dittmar 2014; Koungoulos and Contos 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
