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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Imported Fire Ant and Household Insects Research » Research » Publications at this Location » Publication #390312

Research Project: Management of Fire Ants and Other Invasive Ants

Location: Imported Fire Ant and Household Insects Research

Title: Nuclear genetic diversity of head lice sheds light on human evolution

item Ascunce, Marina
item TOLOZA, ARIEL - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET)
item GONZÁLEZ-OLIVER, ANGELICA - Autonomous National University Of Mexico
item REED, DAVID - University Of Florida

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2023
Publication Date: 11/8/2023
Citation: Ascunce, M.S., Toloza, A.C., González-Oliver, A., Reed, D.L. 2023. Nuclear genetic diversity of head lice sheds light on human evolution. PLOS ONE. 18(11).

Interpretive Summary: Human lice are blood-sucking, wingless, host-specific ectoparasites of humans that are both obligate (cannot live off the host) and permanent (complete their life cycle on a single host). Hundreds of millions of head louse infestations affect children worldwide ever year and numbers continue to rise. The study of the genetic diversity of this human parasite can help in the design of control methods of strategies. In this study, we focused on understanding the genetic diversity of human lice around the world through sampling almost 300 lice from 25 geographic sites around 10 main geographic areas. Using 15 nuclear genetic markers indicated the presense of two main genetic groups amounf human lice worldwide. In addition, there is a significant genetic differentarion among louse populations. For example head lice from Europe have a different genetic profile than head lice from Central America. Furthermore, the louse genetic diversity pattern reveals inter-breeding between different genetic clusters occurring in the Americas, which mirrors human's migration in the continent.

Technical Abstract: The human louse, Pediculus humanus, is an obligate blood-sucking ectoparasite of humans that has coeveolved with humans for millennia. Due to this intimate relationship, the study of human lice has the potential to shed light on aspects of the human evolution that are obscured or lack records. In this study, we analyzed the genetic variation in 274 human lice from 25 geographic sites around the world by using nuclear microsatellite loci and female-inherited mitochondrial DNA sequences. Nuclear genetic diversity analysis revealed the presence of two distinct genetic clusters I and II, while mitochondrial lineages were grouped in two mitochondrial haplogroups: A and B, both of which are present in nuclear Clusters I and II. Only few lice (n=32) showed signs of nuclear hybrid origin with all being found in the New World suggesting recent admixture between louse nuclear cluserd in the New World, mirroring human-host colonization history. These findings were supported by novel DIYABC-simulations that were built using both host and parasite data to define parameters and models. In addition to providing new evoloutionary knowledge about this human parameters and mdoels. In addition to providing new evolutionary knowledge about this human parasite, our study could guide the development of new analyses in other host-parasite systems.