Project description:Species identification of fragmentary bones remains a challenging task in archeology and forensics. A species identification method for such fragmentary bones that has recently attracted interest is the use of bone collagen proteins. We developed a method similar to DNA barcoding that reads collagen protein sequences in bone and automatically determines the species by performing sequence database searches. We tested our method using bone samples from 30 vertebrate species ranging from mammals to fish.
Project description:To investigate immunoediting at the primary tumour, we used DNA barcoding combined with NGS. By stably integrating 4T1 murine cancer cell line with 250000 unique DNA barcodes (1 barcode per cell), we can trace how barcode (and therefore subclonal) diversity changes over time and in the presence of the endogenous immune system, compared to immunocompromised mice.
Project description:We describe the development of a high-sensitivity protein quantification system called HaloTag protein barcoding assay. The assay involves target protein linking to a unique molecule-counting oligonucleotide by click chemistry.
Project description:It is elusive whether clonal selection of tumor cells in response to ionizing radiation (IR) is a deterministic or stochastic process. With high resolution clonal barcoding and tracking of over 400.000 HNSCC patient-derived tumor cells the clonal dynamics of tumor cells in response to IR was analysed. Fractionated IR induced a strong selective pressure for clonal reduction. This significantly exceeded uniform clonal survival probabilities indicative for a strong clone-to clone difference within tumor cells. Survival to IR is driven by a deterministic clonal selection of a smaller population which commonly survives radiation, while increased clonogenic capacity is a result of clonal competition of cells which have been selected stochastically. The ratio of these parameters is amenable to radiation sensitivity which correlates to prognostic biomarkers of HNSCC. Evidence for the existence of a rare subpopulation with an intrinsically radiation resistant phenotype was found at a frequency of 0.6-3.3%. With cellular barcoding we introduce a novel functional heterogeneity associated qualitative readout for evaluating the contribution of stochastic and deterministic clonal selection processes in response to IR.
Project description:Most human breast cancers have already diversified genomically when they first become clinically evident, by which time extensive heterogeneous histopathologies, transcriptomes and growth patterns are also apparent. Accordingly, important initial events and the cellular context in which they occur have been difficult to characterize. Using DNA barcoding, we now demonstrate the high efficiency with which both purified basal and luminal cells isolated directly from normal adult human mammary tissue can be rapidly transformed by a single oncogene (KRASG12D) resulting in the production within 8 weeks in vivo of serially transplantable, polyclonal, invasive ductal carcinomas that are phenotypically heterogeneous and transcriptionally distinct from the initial cells transduced. Barcoding also revealed a consistent dramatic change in the clonal content of passaged tumours. This system thus provides a powerful new platform for examining early events in the genesis, evolution and treatment response of malignant human mammary cells generated using defined mutations.
