Figure
3. Comparison of PCR-free kits for the preparation of
Illumina-compatible sequencing libraries. Libraries were prepared in
triplicate from 200 ng of fragmented PhiX174 DNA (average fragment size
289 bp) using three different PCR-free kits: KAPA HyperPrep (KAPA),
NxSeq AmpFREE Low DNA (NxSeq) and NEBNext Ultra II (NEBNext).(a) Size distribution profiles of DNA libraries. The quality of
DNA libraries was determined on Agilent Bioanalyzer 2100 instrument. One
representative electrophoregram per kit is shown (KAPA in blue, NxSeq in
green and NEBNext in red). The black arrow indicates the localization of
free adapter dimers. (b) Concentration of adapter-ligated
fragments determined by qPCR KAPA. The concentration of DNA fragments
that are ligated with two adapters was determined by qPCR KAPA, after
the first (post-purification 1) and the second (post-purification 2)
SPRI beads purification step. The concentration obtained in a total
volume of 50 µL after the first purification step was normalized to the
final volume of the libraries (20 µL). Bars represent the mean
concentration ± standard deviation of libraries from 3 replicates.
Concentrations obtained were compared by a one-tailed Mann-Whitney test.
ns, p > 0.05; *, p ≤ 0.05.