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  • 50 bp DNA Ladder


    A number of proprietary plasmids are digested to completion with appropriate restriction enzymes to yield 17 bands suitable for use as molecular weight standards for agarose and polyacrylamide gel electrophoresis. The digested DNA includes fragments ranging from 50-1,350 base pairs. The 200 and 500 base pair bands have increased intensity to serve as reference points.

    Comes supplied with 1 vial of Gel Loading Dye, Blue (6X).


    50 bp DNA Ladder visualized by ethidium bromide staining on a 1.8% TBE agarose gel. Mass values are for 1 µg/lane.

    Properties and Usage



    Effective Size Range

    50bp to 1,350bp

    Storage Temperature


    Storage Conditions

    10 mM Tris-HCl
    1 mM EDTA
    pH 8.0 @ 25°C


    1. The 50 bp DNA Ladder was not designed for precise quantification of DNA mass but can be used for approximating the mass of DNA in comparably intense samples of similar size.
    2. All ends have 5´ overhangs that can be end labeled using T4 Polynucleotide Kinase (#M0201) or filled-in using DNA Polymerase I, Klenow Fragment (#M0210) (1). Use α-[32P] dCTP or α-[32P] dGTP for the fill-in reaction.
    3. 50 bp DNA Ladder is stable for at least 3 months at 4°C.
    4. For long term storage, store at -20°C. If samples need to be diluted, use TE or other buffer of minimal ionic strength. DNA may be denatured if diluted in dH2O.
    5. We recommend loading 0.5-1.0 µg of 50 bp DNA Ladder diluted in sample buffer.
    6. 1X Gel Loading Dye, Blue:
      2.5% Ficoll-400
      11 mM EDTA
      3.3 mM Tris-HCl (pH 8.0@25°C)
      0.017% SDS
      0.015% bromophenol blue
    7. Due to the limitations of the acrylamide gel technology, one or two extra bands may be visible on the DNA ladders when run on a polyacrylamide gel.


    1. Sambrook, J., Fritsch, E.F. and Maniatis, T. (1989). Molecular Cloning: A Laboratory Manual, (2nd ed.). 10.51-10.67.

    Supporting Documents

    Material Safety Datasheets

    The following is a list of Material Safety Data Sheets (MSDS) that apply to this product to help you use it safely. The following file naming structure is used to name these document files: [Product Name] MSDS. For international versions please contact us at info@neb.com.


    The Product Summary Sheet, or Data Card, includes details for how to use the product, as well as details of its formulation and quality controls. The following file naming structure is used to name the majority of these document files: [Catalog Number]Datasheet-Lot[Lot Number]. For those product lots not listed below, please contact NEB at info@neb.com or fill out the Technical Support Form for appropriate document.
    1. Why are there extra bands visible on polyacrylamide gels?
    2. Why is the separation of the lower bands incomplete?
    3. What are the overhangs on the DNA ladder fragments? Can I end-label them using the T4 polynucleotide kinase (PNK)? What about the Klenow fragment?
    4. Why are the DNA ladders showing up on my Southern blot? What is the sequence or composition of the ladder bands?
    5. How can I quantify the amount of DNA in each band of a marker?
    6. Can I use GelRed with the DNA Ladders from NEB?
    7. Can I use SYBR® with the DNA Ladders from NEB?
    8. Can I use Midori Green with the DNA Ladders from NEB?
    1. Suggested protocol for loading a sample (N3236)
    2. End-labeling Protocol
    3. Suggested protocol for loading a sample

    Selection Tools

    To make it ready-to-load, dilute in TE buffer instead of water.