Genetic variation in crops of the second millennium bce revealed by ancient DNA analysis

Abstract

For millennia, the Anatolian plateau has functioned as a major migratory corridor between Africa, Asia, and Europe and has subsequently been shaped by shifting settlement patterns, ranging from small communities to complex urban and imperial systems. These processes were closely associated with the development and diversification of agricultural practices. Archaeobotanical investigations at Kaymakçı, a Middle and Late Bronze Age (ca. 3500 years BP) site located in the middle Gediz Valley of western Anatolia, have provided substantial evidence of crop cultivation in the region. In this study, genetic variation in barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), bitter vetch (Vicia ervilia (L.) Willd.), and grape (Vitis vinifera L.) was investigated through the analysis of ancient seeds and comparison with geographically proximate modern samples. Ancient DNA extracted from charred seeds was analyzed using ribosomal (26S rDNA), chloroplast gene (rbcL), and nuclear microsatellite (SSR) markers. Sequence analyses of 26S rDNA and rbcL revealed high levels of similarity between ancient and modern samples, consistent with the conserved nature of ribosomal and plastid gene regions and supporting the taxonomic identification of the archaeobotanical remains. Microsatellite data provided additional exploratory insights into allelic patterns observed in ancient and modern samples. The genetic data presented here provide a molecular perspective on Bronze Age crop remains from western Anatolia and contribute to the growing archaeogenetic record of ancient plant remains in the region.