Genetic affinities between an ancient Greek colony and its metropolis: the case of Amvrakia in western Greece

Background The complex historical phenomenon known as Greek colonization refers to the strategic establishment of new settlements (colonies) from the 8th to the early 4th century BCE. Unlike earlier migrations, this process was planned and driven by the need to expand trade, access resources, and develop economic as well as political networks. Corinth, a prominent commercial center in southern Greece, constitutes a prominent example for initiating colonization. By founding colonies, Corinth established a safe and continuous route for moving goods along the coasts of western mainland Greece and the Adriatic. Amvrakia was one of Corinth’s principal colonies along this route in northwestern Greece. Founded in the 7th century BCE, Amvrakia was characterized by a strong dependence on its metropolis (Corinth). Here, we aim to investigate the genetic relationships between the Corinthian metropolis and the Amvrakia colony, the contribution of the local population to the founding genetic pool, as well as the demography of Amvrakia in subsequent periods. Results During its foundation in the Archaic period, Amvrakia appears to have been shaped by genetic influences from a single source. This source migrated from the Corinth territory, represented by the Archaic Tenea population and is supported via an Identity By Descent (IBD) analysis. A direct ancestry from Late Bronze Age (LBA) Greece, including a local LBA population represented by the Ammotopos site located in close proximity to Amvrakia, was not inferred despite conducting a plethora of independent population genomics analyses. During the subsequent Classical and Hellenistic periods, the population of Amvrakia appears to have only slightly differentiated and evidence of genetic continuity over time is observed. Conclusions The migration of Corinthians to Amvrakia was the major contributor to the initial genetic pool of the colony, indicating that the Corinthian colonization included both genetic and cultural transmission between the metropolis and its colony.