Correlation between molecular and conventional genealogies in Aicuña: a rural population from Northwestern Argentina

Abstract

Aicuña is a village in the northwest of Argentina, located about 300 km south of La Rioja city, in the province of La Rioja. The population of Aicuña derives from a founder couple established in the uninhabited Aicuña valley in the early years of the 17th century. Due to land ownership litigation, the descendants maintained a well-documented genealogy that extends for 12 generations, comprising more than 8,000 individuals. From the historical pedigree of Aicuña, we selected 14 males with direct patrilineal descent from the 2 most ancient male founders, and 23 donors (9 females and 14 males) with direct matrilineal descent from the most ancient female founder. All 3 founders lived in the 17th century. We collected DNA from buccal swabs and characterized the mitochondrial DNA (mtDNA) and Y haplotypes using 14 Y-specific markers, 11 mtDNA polymorphic markers and sequencing of the mt hypervariable regions 1 and 2. We found four different Y haplotypes: Y1 and Y2 haplotypes of European origin corresponding to the founder ancestors Francisco Páez de Espinoza and Apolinario Ormeño, which were shared by 6 and 3 donors, respectively. Three males selected as Ormeño patrilineal descendants showed a different Y haplotype (Y3), probably originated by erroneous paternity registration due to illegitimacy. The remaining case (haplotype Y4), also assumed to belong to the Ormeño lineage, was probably also due to an erroneously registered paternity. Twenty-two donors showed an association of mtDNA markers corresponding to the Amerindian haplotype A2. The founder of this matrilineage could be traced back for more than 14 generations. The haplotype B of one remaining female did not correspond with the historical pedigree and could be due to an error in the genealogy registration. Our results showed an 85% agreement between conventional and molecular genealogies, with mtDNA markers being Amerindian, and Y markers being European. The methodology used in this report is a tool which could potentially be employed as a precedent for land ownership by Aicuña villagers and Amerindian populations.