Product Class: Nucleic Acid Marker

1 kb DNA Ladder

Now comes supplied with 1 vial of Gel Loading Dye, Purple (6X), no SDS (B7025).
Catalog #SizeConcentrationGel Lanes
N3232S0.2 ml500 μg/ml200
N3232L1 ml500 μg/ml1000


A number of proprietary plasmids are digested to completion with appropriate restriction enzymes to yield 10 bands suitable for use as molecular weight standards for agarose gel electrophoresis. The digested DNA includes fragments ranging from 0.5-10.0 kilobases (kb). The 3.0 kb fragment has increased intensity to serve as a reference band. The approximate mass of DNA in each of the bands is provided (assuming a 0.5 μg load) for approximating the mass of DNA in comparably intense samples of similar size.

Comes supplied with 1 vial of Gel Loading Dye, Purple (6X), no SDS.


1 kb DNA Ladder visualized by ethidium bromide staining on a 0.8% TAE agarose gel. Mass values are for 0.5 µg/lane.

Reagents Supplied

The following reagents are supplied with this product:

Store at (°C)Concentration
Gel Loading Dye, Purple (6X), no SDS256X

Properties and Usage



Effective Size Range

500bp to 10,002bp

Storage Temperature


Storage Conditions

10 mM Tris-HCl
pH 8.0 @ 25°C

Supporting Documents

The Certificate of Analysis (COA) is a signed document that includes the storage temperature, expiration date and quality control's for an individual lot. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]_[Lot Number]
The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.
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 or fill out the Technical Support Form for appropriate document.


  1. This 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. We recommend loading 0.5 μg of 1 kb DNA Ladder diluted in sample buffer.
  3. All fragments have a 4-base, 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] dATP or α-[32P] dTTP for the fill-in reaction.
  4. 1 kb DNA Ladder is stable for at least 3 months at 4°C.
  5. 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 denature if diluted in dH20.
  6. 1X Gel Loading Dye, Purple (6X), no SDS:
    2.5% Ficoll®-400 
    10mM EDTA 
    3.3mM Tris-HCL (pH 8.0@25°C)
    0.02% Dye 1 
    0.001% Dye 2 
  7. When DNA ladders are run on a polyacrylamide gel, some reference bands may separate due to nucleic acid composition


  1. Sambrook, J., Fritsch, E.F. and Maniatis, T. (1989). Molecular Cloning: A Laboratory Manual (2nd Ed.). 10.51-10.67.
  1. Why are there extra bands visible on polyacrylamide gels?
  2. 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?
  3. Why are the DNA ladders showing up on my Southern blot? What is the sequence or composition of the ladder bands?
  4. How can I quantify the amount of DNA in each band of a marker?
  5. Can I use GelRed with the DNA Ladders from NEB?
  6. Can I use Midori Green with the DNA Ladders from NEB?
  7. Can I use SYBR® with the DNA Ladders from NEB?
  1. End-labeling Protocol
  2. Suggested protocol for loading a DNA Ladder/marker

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