Genomic detection of a secondary family burial in a single jar coffin in early Medieval Korea

Abstract Objectives Family relationship is a key to understand the structure of past societies but its archeological reconstruction mostly stays circumstantial. Archaeogenetic information, especially genome-wide data, provide an objective approach to accurately reconstruct the familial relationship of ancient individuals, thus allowing a robust test of an archaeology-driven hypothesis of kinship. In this study, we applied this approach to disentangle the genetic relationship of early Medieval individuals from Korea, who were secondarily co-buried in a single jar coffin. Materials and Methods We obtained genome-wide data of six early Medieval Korean individuals from a jar coffin. We inferred the genetic relatedness between these individuals and characterized their genetic profiles using well-established population genetics methods. Results Congruent with the unusual pattern of multiple individuals in a single jar coffin, genome-wide analysis of these individuals shows that they form an extended family, including a couple, their two children and both paternal and maternal relatives. We show that these early Medieval Koreans have a genetic profile similar to present-day Koreans. Discussion We show that an unusual case of the secondary multiple burial in a single jar coffin reflects family relationship among the co-buried individuals. We find both paternal and maternal relatives co-buried with the nuclear family, which may suggest a family structure with limited gender bias. We find the genetic profile of early Medieval Koreans similar to that of present-day Koreans, showing that the genetic root of the present-day Koreans goes back at least 1500?years in the Korean peninsula.1 Introduction 2 Materials and methods 2.1 Archeological context of the Gunsan jar coffin 2.2 Permission for destructive analyses of skeletal elements 2.3 Skeletal analysis 2.4 Sampling of skeletal materials 2.5 Ancient DNA laboratory work and sequencing 2.6 Ancient DNA sequencing data processing and authentication 2.7 Reprocessing of whole genome sequences of present-day Koreans 2.8 Data set compilation 2.9 Principal component analysis 2.10 Genetic kinship analysis 2.11 Runs of homozygosity analysis 2.12 F-statistics and qpWave/qpAdm analysis 3 Results 3.1 | Ancient genome-wide data production 3.2 | A familial relationship of individuals from a single jar coffin 3.3 | The genetic profile of early medieval Koreans 4 Discussio