Studying ancient DNA isolation on human bones found in Kültepe-Kanesh excavations

This thesis focuses on the isolation of ancient DNA from Bronze Age human skeletal remains excavated at the Kültepe-Kanesh site in Kayseri between the 2006-2020 archaeological excavation seasons. Petrous bones, which are the best preservers of DNA among skeletal remains, were used to isolate ancient DNA. 56 individuals whose petrous bones were well-preserved were included in the study and a tooth was sampled from an individual. These samples belonged to 36 adult and 21 non-adult individuals. The skeletons to which the samples belong were recovered from two areas within the site: Tepe (Mound) and Karum (Lower City). 11 samples dated to the Early Bronze Age and 46 samples dated to the Middle Bronze Age. These skeletons were found in three different burial types: simple inhumations, jar burials, and stone cist graves. After the isolation process of the samples, their libraries were prepared and sent for preliminary sequencing. Based on the ratio of human DNA they contained, the preliminary sequencing results of the samples were classified as successful (above 5 ‰) and unsuccessful (below 5 ‰). According to these results, 29 samples (50.9% of the sample group) were found to be successful in terms of extracted human DNA content. The number of unsuccessful samples was 28. Factors affecting this result, such as the climate of the region and the pH level of the soil in Kültepe, are discussed. The possible reasons for the difference between the DNA ratios such as period, area, grave type, presence or absence of metal objects in the graves, age at death of the individuals, and the state of preservation of the bones were evaluated. Although no statistically significant relationship was found between these factors and the DNA ratio, some differences observed indicate that the relative old date of the samples and the presence of metal objects in the graves may negatively affect DNA preservation.