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When can PCR duplicates be removed?
PCR duplicate removal is a recommended step in nearly every variant calling pipeline for NGS data. It is a both a memory and time intensive step, and results in varying percentages of reads being removed. There is no question about whether or not removed reads are valid, or real, sequence reads.
What happens during inversion?
Inversions. An inversion occurs when a chromosome breaks in two places; the resulting piece of DNA is reversed and re-inserted into the chromosome. Genetic material may or may not be lost as a result of the chromosome breaks.
How can a duplicate gene originate?
Gene duplication
- Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution.
- Duplications arise from an event termed unequal crossing-over that occurs during meiosis between misaligned homologous chromosomes.
Is it possible to remove duplicates from RNA Seq?
The vast majority of RNA-seq data are analyzed without duplicate removal. Duplicate removal is not possible for single-read data (without UMIs). De-duplification is more likely to cause harm to the analysis than to provide benefits even for paired-end data (Parekh et al. 2016; below).
How is Umi incorporation used in RNA Seq?
UMI incorporation and library amplification in UMI RNA-seq experiments (Dixit 2016). After deep sequencing, raw data are preprocessed to remove adapter sequences and low quality reads. UMIs in RNA-seq data can be identified using umitools reformat_fastq. PCR duplicates are marked using umitools mark_duplicates.
Can a RNA Seq experiment be done with PCR?
Even though PCR paranoia is understandable, labs need not give into it in all instances. Schroth and his Illumina team have found that PCR issues have a “very, very minimal” effect in a typical RNA-sequencing (RNA-seq) experiment.
Can you remove PCR duplicates without Umi information?
We show that removing PCR duplicates using UMI information is accurate, whereas removing PCR duplicates without UMIs is overly aggressive, eliminating many biologically meaningful reads.