Question: Physical/Fragment Coverage for Paired-Ends: Read Length
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gravatar for QVINTVS_FABIVS_MAXIMVS
11 months ago by
USA SoCal
QVINTVS_FABIVS_MAXIMVS2.1k wrote:

Very quick question:

I am using this method to calculate coverage:

Coverage = N_reads * (average_read_length / haploid_genome_size)

when calculating physical coverage for paired-ends, is "average_read_length" the average of the DNA fragment lengths (length of read1 + insert length + length of read2) or is it the length of the reads (read1+read2)

I think it's the fragment length/template length, right?

coverage • 373 views
ADD COMMENTlink modified 11 months ago by Devon Ryan85k • written 11 months ago by QVINTVS_FABIVS_MAXIMVS2.1k

Does "N_reads" represents the number of reads or the number of fragments/spots that were sequenced?

ADD REPLYlink written 11 months ago by piet1.5k

You would not know the length of the fragment. It would be plain average_read_length in terms of bases. This would be a rough estimate of coverage for the genome based on the number of bases you sequenced and the size of the genome. The formula may need to be Coverage = (N_reads * average_read_length) / haploid_genome_size

ADD REPLYlink modified 11 months ago • written 11 months ago by genomax57k
0
gravatar for Devon Ryan
11 months ago by
Devon Ryan85k
Freiburg, Germany
Devon Ryan85k wrote:

It depends on what sort of coverage you want to calculate. If you're doing variant calling, then you care about how many reads are providing information about the bases at each position, so just the average read length (or sum of reads for PE datasets). If you're doing something like peak calling then you care more about how much data can be used to find peaks, so you'd use the fragment length.

ADD COMMENTlink written 11 months ago by Devon Ryan85k
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