Cat.# 20111S, 20111L: Library size >10 kb (for long-read sequencing)

Gel images of different ranges of library size selection. Sheared human genomic DNA was used as input.

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Library size selection is an enrichment of a specific range of library sizes for NGS library preparations. The NGS library preparation is related to the quality of the sequencing data. Precise NGS library size selection can increase sequencing efficiency, improve data quality, and reduce costs.

There are two types of sequencing technologies: short-read sequencing and long-read sequencing. Short-read sequencing uses DNA libraries that contain small insert DNA fragments of similar sizes, usually several hundred base pairs. The sequencing efficiency can be improved if the DNA size selection is in the right range. Cat.# 20104S and 20104L are the best kits for NGS library size selection of illumina paired-end 100 (PE100) sequencing with 100-200 bp library inserts; Cat.# 20105S and 20105L are the best kits for NGS library size selection of illumina paired-end 150 (PE150) sequencing with 150-300 bp library inserts; and Cat.# 20106S and 20106L are the best kits for NGS library size selection of illumina paired-end 300 (PE300) sequencing with 300-600 bp library inserts.

Long-read sequencing uses a large DNA fragment as input and makes very long reads. Usually, library size selection is preferred to remove smaller fragments. Cat.# 20110S and 20110L are the best kits for long-read sequencing size selection with DNA sizes >5 kb, and Cat.# 20111S and 20111L are the best kits for long-read sequencing size selection with DNA sizes >10 kb.

The magnetic beads, or SPRI (Solid Phase Reversible Immobilization) beads, is well used for the purification of DNA due to their reversible DNA binding. The NGS library can be size-selected by the magnetic beads or SPRI beads. The properties of the magnetic beads can be changed for a specific range of DNA binding. The contaminants and other unwanted components in the libraries can also be removed during size selection.

Specific ranges of NGS libraries can be selected using magnetic beads with different buffer compositions. The first DNA-beads binding step, also called the right-side clean-up, removes large NGS library fragments. The large NGS library fragments that bind to the beads are discarded with the beads pellet. The desired NGS library fragments in the supernatant are transferred to a new well, and new beads are added to the supernatant for the second beads-DNA binding, also called the left-side clean-up. After the rinsing step, the NGS library fragments with the dual selection are eluted in water or an appropriate buffer. The magnetic beads method has great advantages over time-consuming column purification and tedious gel-based purification.

NGS library size selection with dual clean-ups.

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Library size selection for long-read sequencing only requires a single clean-up. In this case, only the large library fragments are bound to the beads, while other small library fragments are discarded with the supernatant. The selected larger library fragments are eluted in water or an appropriate buffer after the rinsing step.

NGS library size selection with single clean-up for >5 kb and >10 kb libraries.

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Features of NGS library size selection

• • • 5 ranges for NGS library size selection
      • • illumina PE100 sequencing: 250-350 bp
        • illumina PE150 sequencing: 300-450 bp
        • illumina PE100 sequencing: 450-750 bp
        • Long-read sequencing: >5 kb
        • Long-read sequencing: >10 kb
    • Rapid protocol: only 20 minutes
    • Simple workflow
      • • No columns required
        • No gel purification required
        • No centrifugation required