Elimination of DNA fragments

What are DNA Fragment Elimination Kits?

DNA fragment elimination kits - also called short fragment removal or short read eliminator (SRE/SFE) kits - selectively deplete DNA fragments below a defined size threshold from high-molecular-weight genomic DNA preparations, enriching the long-fragment population that maximizes read length performance on Oxford Nanopore Technologies (ONT) and PacBio HiFi long-read sequencing platforms. The kits use size-selective precipitation: a proprietary PEG-salt buffer precipitates long DNA (>25 kb) while short fragments remain in solution and are discarded during the wash step, increasing mean fragment size and sequencing N50 without re-extraction or gel electrophoresis. Use a short fragment elimination kit whenever long-read library preparation requires input DNA with a mean fragment size >50 kb, and your extracted HMW DNA contains a significant population of short fragments (<25 kb) that would reduce pore occupancy efficiency on ONT or reduce HiFi polymerase processivity on PacBio.

What you will find:

• Short Fragment Depletor-10 HT (SFD-10HT) is a high-performance reagent designed to eliminate fragments below 10 kb, significantly improving N50 metrics for Oxford Nanopore and PacBio platforms.

• Dual-action technology that simultaneously removes contaminants and concentrates dilute HMW DNA samples within a 65-minute protocol.

• A bead-based, centrifugation-free workflow that ensures reproducibility-tested results across a wide input range (10-150 ng/µL).

• Optimized for amplicons, sheared genomic DNA, and library cleanup, delivering transfection-grade purity with recovery efficiencies up to 90%.

How to Choose a DNA Fragment Elimination Kit

Platform-Specific Kits

The ONT Short Fragment Eliminator Kit (EXP-SFE001) is specifically designed and validated by Oxford Nanopore Technologies for use before ONT ligation-based library preparation (SQK-LSK114, SQK-ULK114). It depletes fragments up to 25 kb, with near-complete removal of those below 10 kb. The PacBio Short Read Eliminator (SRE) Kit is included with PacBio Nanobind extraction kits and validated for SMRTbell library preparation. Use the platform-specific SRE/SFE kit validated by the sequencing instrument manufacturer for guaranteed compatibility with downstream library preparation protocols.

Input DNA Mass and Quality

Both ONT and PacBio SRE/SFE kits require 3-10 ug of high-quality, homogeneous HMW DNA input. Inhomogeneous or gelatinous DNA (incompletely dissolved after extraction) must be warmed to 37-50 degrees C and gently rotated until fully in solution before SFE buffer addition. Confirm homogeneity by triplicate Qubit BR dsDNA measurements from the top, middle, and bottom of the sample tube - values within 10% indicate a homogeneous solution ready for size selection.

Fragment Size Confirmation Before Treatment

Always characterize the input DNA fragment size distribution by Femto Pulse or Genomic DNA ScreenTape before applying short fragment elimination. If the N50 of the input is already >50 kb and the fraction of fragments below 10 kb is <10% by mass, short fragment elimination may not be needed. Apply SRE/SFE only when a significant short fragment population (>20% by mass below 25 kb) would reduce sequencing read length performance.

Post-Elimination QC

After SRE/SFE treatment, always measure recovered DNA mass by Qubit BR Assay and confirm fragment size distribution by Femto Pulse. Expect 40-70% mass recovery (short fragments are discarded), with a significant shift in mean fragment size from the input distribution. The N50 increase from SRE/SFE treatment directly predicts sequencing N50 improvement - a 2-5-fold increase in DNA N50 typically produces a comparable improvement in sequencing read N50.

Alternative Size Selection Methods

For lower-input samples where SRE/SFE precipitation requires more DNA than available, consider: (1) BluePippin or SageELF electrophoretic size selection for precise size cutoffs from limited input (500 ng minimum on some instruments); (2) pulse-field gel electrophoresis followed by electroelution for preparative-scale size selection of very large fragments; (3) AMPure XP beads at low bead ratios (0.3-0.45x) for crude removal of fragments below 5-10 kb, though precision is lower than SRE kits.

Specifications Context

The ONT Short Fragment Eliminator Kit (EXP-SFE001) is designed to remove DNA fragments up to 25 kb, with fragments under 10 kb being almost completely removed. Recommended input is 3-10 ug of unsheared HMW gDNA; shearing before SFE is not recommended as it leads to lower recovery. The Agilent FemtoPulse system is the recommended instrument for evaluating fragment length profiles before and after treatment. A 2022 Frontiers in Plant Science publication (PMC9161206) demonstrated that short fragment removal using the Circulomics SRE kit improved average read length and increased the proportion of ultra-long sequenced fragments (>100 kb) in plant long-read sequencing workflows. Short fragment elimination is a standard pre-library-preparation step for ultra-long-read ONT workflows and PacBio HiFi sequencing at genomics core facilities, including those at Howard Hughes Medical Institute, Vanderbilt University, and MD Anderson Cancer Center.

Maximize your read lengths and silence the short-fragment noise—contact the MBP team today to secure a quote for your SFD-10HT reagents.