Intergenerational transmission of ancestry information in a mid-sized city in Argentina

MARCELA MENDOZA; BÁRBARA MAZZA; GRACIELA CABANA; LINDSAY SMITH; DI FABIO ROCA, FRANCISCO; HUGO DELFINO; CARLA MARTÍNEZ

Latin American and Caribbean Ethnic Studies

Taylor & Francis Online

Año: 2022

1744-2222

We analyzed self-reported family trees of 288 adult Argentine residents of a mid-sized city within the megacity of Buenos Aires to evaluate ways in which intergenerational transmission of ancestry information matched (or not) anonymized estimates of continental-level genetic ancestry. Intergenerational transmission of ancestry information was inferred from the content of the anonymized family trees, and continental-level ancestries were inferred from genomic information collected from residents. We found a high degree of concordance between genetic ancestry estimates and the transmission of ancestry information in the case of ancestors born in Europe, the Middle East, and Southeast Asia (Japan). We found the converse in the case of ancestors who were Indigenous American, sub-Saharan African, or their descendants. Few participants reported Indigenous ancestors, and none reported ancestors of sub-Saharan African-descent. Yet, the existence of those ancestors was evident in their genetic ancestry estimates. We extrapolated the presence of such ancestries in family trees on a post hoc basis, by deducing that some ancestors identified as ?Argentine? in family trees were likely of mixed Indigenous- and non-Indigenous-descent, and possibly also sub-Saharan African descent. We describe these findings as due to a process of attrition, in which some ancestries, but not others, have been forgotten (whether knowingly or unknowingly) over the course of generations, to the point that present-day participants were unaware that mixing or mestizaje occurred within their own families.