Mitochondrial diversity in human head louse populations across the Americas

Abstract

Anthropological studies suggest that the genetic makeup of human populations in the Americas is the result of diverse processes including the initial colonization of the continent by the first people plus post-1492 European migrations. Because of the recent nature of some of these events, understanding the geographical origin of American human diversity is challenging. However, human parasites have faster evolutionary rates and larger population sizes allowing them to maintain greater levels of genetic diversity than their hosts. Thus, we can use human parasites to provide insights into some aspects of human evolution that may be unclear from direct evidence. In this study, we analyzed mitochondrial DNA (mtDNA) sequences from 450 head lice in the Americas. Haplotypes clustered into two well-supported haplogroups, known as A and B. Haplogroup frequencies differ significantly among North, Central and South America. Within each haplogroup, we found evidence of demographic expansions around 16,000 and 20,000 years ago, which correspond broadly with those estimated for Native Americans. The parallel timing of demographic expansions of human lice and Native Americans plus the contrasting pattern between the distribution of haplogroups A and B through the Americas suggests that human lice can provide additional evidence about the human colonization of the New World.

Head Lice of Pygmies Reveal the Presence of Relapsing Fever Borreliae in the Republic of Congo

“…In addition to inter-haplogroup diversity, P . humanus also presents intra-haplogroup diversity, illustrated by many distinct A, B and C haplotypes [2, 12, 39]. These results are supported by our finding, that, of the 160 head lice cytb sequences analysed, 15 different haplotypes were identified, of which 11 were novel.…”

“…Clade A lice are most likely to have emerged in Africa and to have evolved on the host linage that led to anatomically modern humans ( Homo sapiens ), showing the signs of a recent demographic expansion out of Africa about 100,000 years ago, first to Eurasia and subsequently to Europe, Asia, and the New World [1, 5, 12]. Haplogroup B diverged from haplogroup A between 0.7 and 1.2 MYA and may have evolved on archaic hominids, such as the Homo sapiens neanderthalensis , who spread across Europe and Asia, only becoming associated with modern humans during the period of overlap as the result of a recent host switch [1, 5, 12]. …”

Killer cell immunoglobulin‐like receptor (KIR) gene diversity in a population naturally exposed to malaria in Porto Velho, Northern Brazil

“…The two most common genotypes in the Porto Velho communities, genotypes 1 and 2, are common in many other populations. However, the frequencies were similar to those observed in the North, Central and South Americas (http://www.allelefrequencies.net), which is consistent with the results of mitochondrial DNA and classical markers studies reflecting the human demographic history of the American continent, starting with the first settlement of the Americas by Asians across the Bering Strait approximately 15–18 thousand years ago plus post‐Columbus migrations with more than five centuries of admixture between Natives Americans, Europeans, Africans and modern Asians .…”

Where Are We With Human Lice? A Review of the Current State of Knowledge

“…Six mitochondrial clades were described (A, D, B, F, C, and E) (Ashfaq et al, 2015;Drali et al, 2015b;Amanzougaghene et al, 2016bAmanzougaghene et al, , 2017Amanzougaghene et al, , 2019. In addition to the inter clade diversity, human lice also display intra clade diversity, as illustrated by the multiple distinct haplotypes for each clade ( Figure 1B) (Ascunce et al, 2013;Ashfaq et al, 2015;Amanzougaghene et al, 2016a;Drali et al, 2016a). Head lice encompass all clades diversity, while body lice belong to clades A and D only (Amanzougaghene et al, 2017).…”