A sample preparation for a nucleic acids sequencing assay. Intended insert size In paired-end sequencing, the DNA between the adapter sequences is the insert. The length of this sequence is known as the insert size, not to be confused with the inner distance between reads. So, fragment length equals read adapter length (2x) plus insert size, and insert size equals read lenght (2x) plus inner distance. FG:0000001 FG_0000001