Project description:Long-term balanced fertilization decreases arbuscular mycorrhizal fungal diversity in a north Chinese arable soil revealed by 454 pyrosequencing
Project description:The international DNA sequence databases abound in fungal sequences not annotated beyond the kingdom level, typically bearing names such as "uncultured fungus". These sequences beget low-resolution mycological results and invite further deposition of similarly poorly annotated entries. What do these sequences represent? This study uses a 767,918-sequence corpus of public full-length fungal ITS sequences to estimate what proportion of the 95,055 "uncultured fungus" sequences that represent truly unidentifiable fungal taxa - and what proportion of them that would have been straightforward to annotate to some more meaningful taxonomic level at the time of sequence deposition. Our results suggest that more than 70% of these sequences would have been trivial to identify to at least the order/family level at the time of sequence deposition, hinting that factors other than poor availability of relevant reference sequences explain the low-resolution names. We speculate that researchers' perceived lack of time and lack of insight into the ramifications of this problem are the main explanations for the low-resolution names. We were surprised to find that more than a fifth of these sequences seem to have been deposited by mycologists rather than researchers unfamiliar with the consequences of poorly annotated fungal sequences in molecular repositories. The proportion of these needlessly poorly annotated sequences does not decline over time, suggesting that this problem must not be left unchecked.
Project description:This SuperSeries is composed of the following subset Series: GSE12019: Fine-scale mapping of copy-number alterations with massively parallel sequencing GSE13372: High-resolution mapping of copy-number alterations with massively parallel sequencing Refer to individual Series
Project description:An ability to map the global interactions of a chemical entity with chromatin genome-wide could provide new insights into the mechanisms by which a small molecule perturbs cellular functions. we developed a method that uses chemical derivatives and massively parallel DNA sequencing (Chem-Seq) to identify the sites bound by small chemical molecules throughout the human genome. We developed in vivo and in vitro Chem-Seq protocols with a biotinylated derivative of small molecules. In the in vivo protocol, Cells were first treated with biotinylated ligand and cross-linked with formaldehyde at the same time. Cells were then lysed, sonicated to shear the DNA, and streptavidin beads were used to isolate biotinylated ligand and associated chromatin fragments. We then used massively parallel sequencing to identify the enriched DNA fragments, and mapped these sequences to the genome. In in vitrol protocol, MM1.S cells were fixed and the derived sonicated lysate incubated with biotinylated drug to enrich for bound chromatin regions in vitro. We then used massively parallel sequencing to identify the enriched DNA fragments, and mapped these sequences to the genome.
Project description:DNA methylation is a complex epigenetic marker that can be analysed using a wide variety of methods. Interpretation and visualisation of DNA methylation data can mask complexity in terms of methylation status at each CpG site, cellular heterogeneity of samples and allelic DNA methylation patterns within a given DNA strand. Bisulfite sequencing is considered the gold standard, however visualisation of massively parallel sequencing results remains a significant challenge. We created a program called Methpat that facilitates visualisation and interpretation of bisulfite sequencing data generated by massively parallel sequencing. To demonstrate this, we performed multiplex PCR that targeted 48 regions of interest across 95 human samples. The regions selected included known gene promoters associated with cancer, repetitive elements, known imprinted regions and mitochondrial genomic sequences. We interrogated a range of samples including human cell lines, primary tumours and primary tissue samples. Methpat generates two forms of output: a tab delimited text file for each sample that summarises DNA methylation patterns and their read counts for each amplicon and a HTML file that summarises this data visually. Methpat can be used with publicly available whole genome bisulfite sequencing (WGBS) and reduced representation bisulfite sequencing (RRBS) datasets with sufficient read depths. Using Methpat, complex DNA methylation data derived from massively parallel sequencing can be summarised and visualised for biological interpretation. By accounting for allelic DNA methylation states and their abundance in a sample, Methpat can unmask the complexity of DNA methylation and reveal further biological insight in existing datasets. Multiplex bisulfite PCR and Next Generation sequencing of primary human samples and breast cancer cell lines.
Project description:H3K4me1 binding in murine pre-B cells detected by ChIP-seq. For the ChIP-seq, input and immunoprecipitated DNA was given to the TSRI Next Generation Sequencing Core (the Scripps Research Institute, La Jolla, CA, US), where it was prepared for massively parallel sequencing on Illumina HiSeq2000.
Project description:Reads from massively parallel sequencing of RNA primed, short nascent strands from asynchronously growing cancer cells (K562, MCF7). Newly replicated DNA was isolated based on size (400-800 bp) and the presence of a short RNA stretch at the 5' end using lambda exonuclease. Purified nascent strands were analyzed using massively parallel sequencing. Sheared genomic DNA was sequenced as a control.