Mitochondrial genomes from Bronze Age Poland reveal genetic continuity from the Late Neolithic and additional genetic affinities with the steppe populations.

OBJECTIVE: In this work we aim to investigate the origins and genetic affinities of Bronze Age populations (2,400-1,100 BC) from the region of southern Poland and to trace maternal kinship patterns present in the burials of those populations by the use of complete mitochondrial genomes. MATERIALS AND METHODS: We performed ancient DNA analyses for Bronze Age individuals from present-day Poland associated with the Strzyzow culture, the Mierzanowice culture, and the Trzciniec Cultural circle. To obtain complete mitochondrial genomes, we sequenced genomic libraries using Illumina platform. Additionally, hybridization capture was used to enrich some of the samples for mitochondrial DNA. AMS (14) C-dating was conducted for 51 individuals to verify chronological and cultural attribution of the analyzed samples. RESULTS: Complete ancient mitochondrial genomes were generated for 80 of the Bronze Age individuals from present-day Poland. The results of the population genetic analyses indicate close maternal genetic affinity between Mierzanowice, Trzciniec, and Corded Ware culture-associated populations. This is in contrast to the genetically more distant Strzyzow people that displayed closer maternal genetic relation to steppe populations associated with the preceding Yamnaya culture and Catacomb culture, and with later Scythians. Potential maternal kinship relations were identified in burials of Mierzanowice and Trzciniec populations analyzed in this study. DISCUSSION: Results revealed genetic continuity from the Late Neolithic Corded Ware groups to Bronze Age Mierzanowice and Trzciniec-associated populations, and possible additional genetic contribution from the steppe to the formation of the Strzyzow-associated group at the end of 3rd millennium BC. Mitochondrial patterns indicated several pairs of potentially maternally related individuals mostly in Trzciniec-associated group.