Reconstructing population history using JC virus: Amerinds, Spanish, and Africans in the ancestry of modern Puerto Ricans

The roots of the Hispanic populations of the Caribbean Islands and Central and South America go back to three continents of the Old World. In Puerto R ico major genetic contributions have come from (1) Asians in the form of th e aboriginal Taino population, an Arawak tribe, present when Columbus arriv ed on the Island, (2) Europeans, largely Spanish explorers, settlers, gover nment administrators, and soldiers, and (3) Africans who came as part of th e slave trade. Since JC virus (JCV) genotypes characteristic of Asia, Europ e, and Africa have been identified, and excretion of JCV in urine has been proposed as a marker for human migrations, we sought to characterize the JC V strains present in a Caribbean Hispanic population. We found that the str ains of JCV present today in Puerto Rico are those derived from the Old Wor ld populations represented there: Types 1B and 4 from Spain, Types 3A, 3B, and 6 from Africa, and Type 2A from Asia. The Type 2A genotype represents t he indigenous Taino people. This JCV genotype was represented much more fre quently (61%) than would be predicted by the trihybrid model of genetic adm ixture. This might be attributable to characteristics of JCV Type 2A itself , as well as to the nature of the early relationships between Spanish men a nd native women. These findings indicate that the JCV strains carried by th e Taino Indians can be found in today's Puerto Rican population despite the apparent demise of these people more than two centuries ago. Therefore, mo lecular characterization of JCV provides a tool to supplement genetic techn iques for reconstructing population histories including admired populations .