Project description:HCC827 cells were barcoded using the ClonTracer lentiviral barcode library such that the majority of cells were infected with a single barcode. One million cells were expanded to ~120 million cells and split into 8 HYPERfasks. Two HYPERfasks were grown under DMSO and grown until confluence. In six HYPERfasks cells were grown under a GI90 concentration of one of two different inhibitors, gefitinib and trametinib (3 HYPERfasks each). Cells achieved confluence at 4 and 9 weeks for gefitinib and trametinib respectively. During this time, the medium and inhibitor were replenished weekly and DNA was extracted from the medium to track barcode content from dying cells.
Project description:A widespread assumption for single-cell analyses specifies that one cell’s nucleic acids are predominantly captured by one oligonucleotide barcode. However, we show that ~13-21% of cell barcodes from the 10x Chromium scATAC-seq assay may have been derived from a droplet with more than one oligonucleotide sequence, which we call “barcode multiplets”. We demonstrate that barcode multiplets can be derived from at least two different sources. First, we confirm that approximately 4% of droplets from the 10x platform may contain multiple beads. Additionally, we find that approximately 5% of beads may contain detectable levels of multiple oligonucleotide barcodes. We show that this artifact can confound single-cell analyses, including the interpretation of clonal diversity and proliferation of intra-tumor lymphocytes. Overall, our work provides a conceptual and computational framework to identify and assess the impacts of barcode multiplets in single-cell data.
Project description:Manufacturing adulteration is the major cause of discrepancies between the declared and actual composition of food products. The use of high-throughput sequencing of DNA barcodes is a promising method to identify adulterants, but is not yet widely used in practice. Food pre-processing and differences in GC composition can lead to unequal amplification or complete loss of DNA barcode components, so the results of genomic analysis require an independent confirmation method. Perhaps the most promising way to increase the accuracy of food ingredient identification is to use an orthogonal method based on very different physical principles than DNA sequencing, which involves the analysis of other plant cell components, to verify the results of HTS analysis. In this work, we decided to evaluate the suitability of a multi-omic approach, including coupled DNA barcode HTS analysis and proteomic analysis, to estimate food fraud in herbal beverages. To resolve disputed discordant results obtained during genomic and proteomic investigation of samples, we used traditional botanical morphology method. Among the samples studied, the combined approach revealed two adulterations of Epilobium with Lythrum, which could be dangerous for the unsuspecting consumer.
Project description:Barcode-based multiplexing methods can be used to increase throughput and reduce batch effects in large single-cell genomics studies. To evaluate methods for demultiplexing barcode-multiplexed data, we generated a dataset by labeling samples separately with barcode-tagged antibodies, mixing those samples, and progressively overloading a droplet-based scRNA-seq system.