The Polynesian gene pool: an early contribution by Amerindians to Easter Island

Abstract

It is now generally accepted that Polynesia was first settled by peoples from southeast Asia. An alternative that eastern parts of Polynesia were first inhabited by Amerindians has found little support. There are, however, many indications of a ‘prehistoric’ (i.e. before Polynesia was discovered by Europeans) contact between Polynesia and the Americas, but genetic evidence of a prehistoric Amerindian contribution to the Polynesian gene pool has been lacking. We recently carried out genomic HLA (human leucocyte antigen) typing as well as typing for mitochondrial DNA (mtDNA) and Y chromosome markers of blood samples collected in 1971 and 2008 from reputedly non-admixed Easter Islanders. All individuals carried HLA alleles and mtDNA types previously found in Polynesia, and most of the males carried Y chromosome markers of Polynesian origin (a few had European Y chromosome markers), further supporting an initial Polynesian population on Easter Island. The HLA investigations revealed, however, that some individuals also carried HLA alleles which have previously almost only been found in Amerindians. We could trace the introduction of these Amerindian alleles to before the Peruvian slave trades, i.e. before the 1860s, and provide suggestive evidence that they were introduced already in prehistoric time. Our results demonstrate an early Amerindian contribution to the Polynesian gene pool on Easter Island, and illustrate the usefulness of typing for immunogenetic markers such as HLA to complement mtDNA and Y chromosome analyses in anthropological investigations.

Three Millennia of Climatic, Ecological, and Cultural Change on Easter Island: An Integrative Overview

“…The introduction of new analytical techniques to identify remains of cultigens, as for example phytoliths and starch, has been useful to locate human fingerprints in sedimentary sequences (Horrocks et al, 2012a(Horrocks et al, ,b, 2013(Horrocks et al, , 2015Bowdery, 2014). New developments based on DNA analysis of modern humans and food remains from ancient skeletons have shed new light on the origin of settlers (Thorsby, 2012;Thromp and Dudgeon, 2015). In addition, some new analyses and meta-analyses on radiocarbon dates associated with archeological remains have provided relevant information on human activities, land use and demography (Mulrooney, 2013;Stevenson et al, 2015).…”

Historical collections reveal patterns of diffusion of sweet potato in Oceania obscured by modern plant movements and recombination

“…Genetic analyses have focused not only on human populations (3,4) but also on those of species closely associated with human movements (5-13), including commensal animals (Rattus exulans) (5, 6), domesticated plants [bottle gourd, Lagenaria siceraria (7,8); banana, Musa spp. (9)] and animals [chicken, Gallus gallus (10, 11); pig, Sus scrofa (12)], and pathogens (Helicobacter pylori) (13).…”

Identification of Polynesian mtDNA haplogroups in remains of Botocudo Amerindians from Brazil

“…The presence of the mutation 16247G (HVSI) and 6905A (ancestral allele), further characterized the sequence as belonging to haplogroup B4a1a1a (32)(33)(34). This haplogroup is found at high frequency in Polynesia, Micronesia, parts of Near Oceania, and Easter Island (33)(34)(35)(36).…”

“…Polynesian islands were apparently populated around 3,000 y ago (33,36). Nevertheless, the time to the most recent common ancestor (TMRCA) for the Polynesian motif in Papuans and Polynesians was calculated as 9,300 ± 2,000 y before present (34).…”