GEOGRAPHIC DIVERSITY OF PEDICULUS HUMANUS ACROSS THE AMERICAS

J FANE, MS ASCUNCE, G KASSU, A TOLOZA, MI PICOLLO, D REED

Exposición; Undergraduate student meeting of the University of Florida; 2011

National Science Fundation (NFS)

The human head louse is a highly specialized blood-sucking insect that completes its entire life cycle on the human head. Over millions of years, this close association has led to coevolution in which louse diversification parallels that of humans. Therefore, we can use louse molecular data to infer the evolutionary history of lice and also of their human hosts. All humans populations have lice; however, the genetic diversity of the human louse worldwide is poorly understood. In this study, we analyzed mtDNA from 450 lice in the Americas to gain a better understanding of the louse mitochondrial diversity in these continents. Haplotypes were divided into two well supported groups, known as haplogroup A and B, respectively. We found 12 haplotypes belonging to clade A and 25 in clade B. Haplogroup frequencies differ geographically. Haplogroups A and B were both relatively common in North America, with 58% haplogroup A and 42% haplogroup B. In Central America, haplogroup A was much less common than haplogroup B (18% and 82%, respectively). In contrast, 95% of the head lice from South America belonged to haplogroup A with only 5% of the haplotypes from haplogroup B. We suggest that multiple colonization events throughout the Americas could account for the differing haplogroup frequencies seen today. These events seems to include both the first peopling of the New World from Asia and a more recent European colonization, potentially increasing the genetic diversity in the lice due to admixture. More markers including highly nuclear polymorphic loci, such as microsatellites, are needed to further analyze the genetic diversity of human lice in the Americas.