FPKMs or Fragments Per Kilobase of exon per Million reads . Fragment means fragment of DNA, so the two reads that comprise a paired-end read count as one. Per kilobase of exon means the counts of fragments are then normalized by dividing by the total length of all exons in the gene (or transcript). This bit of magic makes it possible to compare Gene A to Gene B even if they are of different lengths. Per million reads means this value is then normalized against the library size. This bit of magic makes it possible to compare Gene A in Sample 1 to Sample 2 even if Sample 1′s RNA-seq library has 60 million pairs of reads and Sample 2′s library has only 30 million pairs of reads.
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Created: 6th Jul 2016 at 12:58
Last updated: 20th Aug 2021 at 12:19
Last used: 28th Jun 2022 at 21:31