Archaeogenetics reconstructs demography and extreme parental consanguinity in a Bronze Age community from Southern Italy

Abstract

Given its geographic location and unique history of contacts and migrations, Calabria is a core region to investigate the genetic traces of some of the numerous prehistoric demographic events in the Central Mediterranean. However, little is known regarding the ancient populations of the region before Greek colonization, reflecting gaps in the archaeological knowledge of the territory and scarcity of genetic data. Here, we analysed genome-wide data from the Middle Bronze Age site of Grotta della Monaca (1780-1380 ca. BCE) to fill these gaps and decipher funerary practices, social organization, biological kinship ties, and demographic shifts in Southern Italy during the Bronze Age. The community shows closer genetic affinity to Early Bronze Age Sicilians than to contemporaneous populations from the Italian peninsula. However, unlike contemporary Sicilian individuals, they lack eastern genetic influences, suggesting distinct ancestral trajectories and interaction networks among Bronze Age populations. Further, we suggest that burial practices were structured according to the sex and kinship relationships of the deceased. To the best of our knowledge, our data showcase the first case reported in archaeological literature of a parent-offspring incestuous union, an extreme case that we attempt to frame into the demographic landscape of prehistoric communities of Bronze Age Southern Italy.