Marie Connemann

DNA Phenotyping of Single Samples – Implementation of SNaPshot® Multiplex Systems for Reconstruction of Hair, Iris, and Skin Pigmentation with Focus on Degraded DNA

Since the change in the German law, which now also allows the analysis of coding sequences, forensic DNA analysis is increasingly focusing on the possibility of phenotyping. DNA phenotyping comprises the deduction of external characteristics (EVCs) like hair, iris, and skin pigmentation from specific genetic variations known as single nucleotide polymorphisms (SNPs). Besides the significance of DNA phenotyping in forensics, it is also of great importance in the context of provenance research and museal portrayals.
These informative SNPs, found within pigmentation genes, play a crucial role in determining the phenotype. Analysing these SNPs generally requires some form of sequencing. Sequencing approaches that utilise the single base extension method are especially suited towards SNP analyses because they reduce the amount of obtained data to one single base variation, the respective SNP. Multiple methods fall under the category of single base extension, one of them being the so-called SNaPshot® analysis. It encompasses single base extension with SNP analysis via capillary electrophoresis. The major advantages of this method are the cost efficiency and suitability towards the analysis of single samples which are not given when using for example nanofluidic Dynamic Arrays.
My thesis aims to implement and optimize the three in-house SNaPshot® multiplex systems – "IrisPlex", "HairPlex", and "SkinPlex" – for DNA phenotyping of iris, hair, and skin pigmentation. Each system will undergo individual testing and enhancement, focusing on target-specific and SNaPshot® PCR optimization. The goal is to adapt these systems for the use with degraded DNA commonly found in forensic, historic, and prehistoric samples. Ultimately, these multiplex systems should meet current standards and become everyday tools at the Department of Historical Anthropology and Human Ecology in Göttingen. The application of these systems to various forensic, historic, and prehistoric samples aims to validate their utility and suitability in an anthropological and forensic context.