The DNA of head lice preserves a record of the interactions between Europeans and Native Americans. Attribution: Vincent Smith, Natural History Museum, London, licensed under CC-BY 4.0.
A worldwide genetic analysis of lice indicates their introduction into the Americas occurred on two separate occasions with their human hosts.
Marina Ascunce of the USDA-ARS, with her team, presents evidence in a recent study, dated November 8 and available in the PLOS ONE journal, that lice reached the Americas during initial human migration over the Bering Strait and subsequently with European settlers.
Lice as Markers of Human Development
The human louse, a flightless parasite feeding on blood, spends its lifespan attached to its human host. As one of the earliest known human parasites, its evolution has been closely linked with that of humans. The new study examines the genetic differences in 274 lice samples collected from 25 global locations to trace human evolution.
Genetic Patterns Indicating Human Movement
The study’s genetic examination of lice DNA uncovered two separate lice populations with minimal interbreeding. The first, Cluster I, had a global presence, whereas Cluster II was exclusive to Europe and the Americas. Lice in the Americas showing heritage from both clusters suggest a hybrid origin from the earliest migrants and later European-introduced lice.
Asian and Central American Lice Connection
A genetic link between Asian and Central American lice suggests migration from East Asia into North America, leading to the establishment of the first Native American populations, who then moved into Central America. These lice carry genetic markers from their ancient Asian forebears.
Implications for Future Research
This research aligns with current theories on human migration and extends our understanding of lice evolution. The study utilized rapidly evolving genetic markers to investigate recent historical events. Further research with more slowly evolving markers could reveal deeper insights into ancient migrations. The methodologies developed could also inform future host-parasite system studies.
The authors conclude by stating that human lice, as persistent human parasites, serve as indicators of our evolutionary trajectory, having shared millions of years of co-evolution due to their dependence on human blood.
Citation: “Nuclear genetic diversity of head lice elucidates human movement across the globe” by Marina S. Ascunce et al., 8 November 2023, PLOS ONE.
DOI: 10.1371/journal.pone.0293409
Table of Contents
Frequently Asked Questions (FAQs) about human-lice coevolution
What does the DNA of head lice reveal about human history?
The DNA of head lice has recorded the interactions between Europeans and Native Americans, showing evidence of human migration patterns and colonization in the Americas.
How did researchers use lice to understand human migration?
Researchers analyzed genetic variations in lice from various geographic locations to trace the paths of human evolution and migration, finding distinct genetic clusters indicative of different migration events.
What are the implications of the genetic relationship found between Asian and Central American lice?
The genetic link suggests that East Asians migrated to North America, becoming the first Native Americans, and then traveled south into Central America, as modern lice populations there retain genetic traces from their Asian ancestors.
How might future research on lice DNA contribute to our understanding of human history?
Future studies using slower-evolving genetic markers in lice could provide insights into more ancient human migration events and further refine our understanding of human-lice coevolution.
More about human-lice coevolution
- Tracking Human Migration Through Lice DNA
- Lice as Indicators of Human Evolution
- Uncovering the Genetic History of Head Lice
- Genetic Study of Lice and Human Colonization
5 comments
Wow just read about how lice can tell us where we come from thats crazy nature is wild
its fascinating to think that our history is kinda written by such small creatures like lice
Heard about this study at the museum, the link between lice in Asia and Central America? Mind-blowing stuff really
gotta say this is pretty cool, never would’ve thought lice had so much to tell us about the past
lice arriving with the first people and then with europeans, it’s like they were the real stowaways of history.