Changes between Version 4 and Version 5 of SOPs/atac_Seq
- Timestamp:
- 08/11/20 11:07:09 (4 years ago)
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SOPs/atac_Seq
v4 v5 87 87 * The NRF should be > 38bp to < 147 bases (one nucleosome); mono nucleosome fragments are in the range of 147 -200 bp 88 88 * don't recommend to remove di-, tri nucleosome fragments for downstream analysis unless you have a great number of reads. Otherwise the you might miss many open chromatin regions during peak calling. 89 * check fragment size dist (from ATACSeqQC) 89 * check fragment size distribution (from ATACSeqQC) 90 * see [[https://www.nature.com/articles/nmeth.2688/figures/2 | Fig 2]] from Buenrostro, J.D., et al. for expected distribution of fragment size 90 91 * Tn5 produces 5’ overhangs of 9 bases long: pos. strand + 4 and neg strand -5 (shiftGAlignmentsList and shiftReads function) splitGcAlignmentsByCut: creates different bins of reads: nucleosome free regions (NFR), mono, di, etc. Shifted reads that do not fit into any of the bins should be discarded. 91 92 * use housekeeping genes to check QC: signal enrichment is expected in the regulatory regions of housekeeping genes in good ATACSeq eperiments. Use IGVSnapshot function with geneNames param. splitGAlignmentsByCut: creates different bins of reads: NFR, mono, di, etc. Shifted reads that do not fit into any of the bins should be discarded.