For accurate analysis of linear double-stranded DNA in agarose or polyacrylamide gels, researchers can rely on Thermo Scientific DNA ladders with a broad selection of fragment sizes ranging from 10 bp to 48.5 kb. Thermo Scientific DNA ladders are manufactured and quality controlled to high industry standards. DNA ladders are made of chromatography-purified individual DNA fragments using a proprietary technology for preparation of pharmaceutical-grade plasmid DNA. Additionally, DNA ladders are stable for up to six months at room temperature and multiple freeze-thaw cycles, thus helping provide researchers with consistently reliable results.


Understanding the purpose of DNA ladders and molecular weight rulers

What is the purpose of a DNA ladder?

The purpose of DNA ladders in electrophoresis is to serve as a molecular marker or reference point for determining the size of sample DNA fragments. When run alongside experimental samples in a gel, the DNA ladder that is composed of fragments of known lengths allows researchers to estimate the size of unknown DNA fragments.

DNA ladders can also help to indicate that the gel is working properly, based on how the bands appear. 

How much DNA ladder to load?

The amount of DNA ladder to load onto a gel will depend on the specific ladder being used. For a standard agarose gel, typically 1 µL of DNA ladder is mixed with 5 µL of loading dye to make a final volume of 6 µL to load per lane. 


Why you should choose DNA ladders that are shipped under ambient conditions

Embracing eco-friendly practices at work benefits everyone, though it can be challenging in the lab. While completely eliminating waste in molecular biology isn't always feasible, you can significantly reduce packaging and shipping materials throughout your workflow.

Switch to ambient shipping for your nucleic acid electrophoresis experiments with Thermo Scientific DNA ladders. Our testing confirms that product quality and stability remain intact. Go ambient today and:

  • Help minimize waste
  • Use smaller shipping boxes, reducing cardboard use
  • Help eliminate refrigerants, avoiding cold gel packs and dry ice disposal
  • Help reduce the need for expanded polystyrene (EPS) coolers


Thermo Scientific DNA Ladder selection guide

 DNA ladderApplicationAgarose gel resolution timeOriginFormulationLoading dyes supplied
GeneRuler and O'GeneRuler DNA Ladders

To analyze very small or large DNA fragments

Can be run at high voltages or with reused running buffers and agarose gels

10 min–1.5 hrMixtures of individual, chromatography-purified DNA fragmentsIn TE buffer or ready-to-use6X DNA Loading Dye or 6X Orange Loading Dye
MassRuler DNA LaddersTo accurately quantify DNA on a gel10–45 minMixtures of individual, chromatography-purified DNA fragmentsReady-to-use6X MassRuler Loading Dye
FastRuler DNA LaddersHigh-throughput applications8–14 minMixtures of 5 individual, chromatography-purified DNA fragmentsReady-to-use6X MassRuler Loading Dye, 6X Orange Loading Dye
O'RangeRuler DNA LaddersPrecise sizing of DNA enabled by step ladder with exact repeats of a DNA fragment45 min–1.5 hrLigated 5, 10, 15, 20, 50, 100, 200, 500 bp DNA fragmentsReady-to-use6X Orange Loading Dye
ZipRuler Express DNA LaddersFor fast and accurate sizing of a broad range (100–20,000 bp) of DNA fragments10–20 minMixtures of individual, chromatography-purified DNA fragmentsReady-to-use6X Orange Loading Dye, 6X MassRuler Loading Dye
Conventional DNA MarkersAnalysis of large DNA fragments45 min–18 hrDigested lambda, phage and plasmid DNAIn TE buffer or ready-to-use6X DNA Loading Dye
NoLimits Custom DNA LaddersExcellent for creating custom ladders for use in electrophoresis or HPLCComposition dependentIndividual, chromatography-purified DNA fragmentsIn TE buffer or ready-to-useAny Thermo Scientific loading dye upon request


MassRuler DNA Ladders

Product photo. A tube of MassRuler Low Range DNA Ladder, ready-to-use

MassRuler DNA Ladders are specially designed for accurate quantification and sizing of DNA fragments on agarose gels. DNA quantification on gels is sometimes superior to spectrophotometric measurements that do not discriminate DNA, RNA, and nucleotides. The ladders are mixtures of chromatography-purified, individual DNA fragments.

MassRuler DNA ladders are available in both low range (LR) and high range (HR) formats. In the forward versions, the mass of each DNA fragment is directly proportional to the fragment size, whereas in the reverse versions, the mass is inversely proportional to the fragment size.

Features of MassRuler DNA Ladders

Image of agarose gel showing DNA bands of different sizes
  • Accurate DNA quantification on gels—DNA amounts of each band are determined spectrophotometrically
  • Ready-to-use—Premixed with loading dye
  • Room temperature storage for six months
  • Supplied with loading dye for sample DNA


MassRuler DNA Ladders selection guide


FastRuler DNA Ladders

Product photo, 3 tubes of FastRuler DNA ladders

FastRuler DNA ladders are an excellent solution for fast sizing and quantification of PCR products containing single amplicons. The ladders separate in 8–14 min, requiring a relatively short 1–2 cm separation distance on gel. Since minimal agarose is needed for separation, gels can be cast with multiple combs for higher throughput and to save agarose.

Features of FastRuler DNA Ladders

  • Fast separation (8–14 min) in short separation distance (10–20 mm)
  • Fast sizing and approximate quantification
  • Excellent for PCR products
  • Ready-to-use—Premixed with loading dye
  • Stable at room temperature for six months
  • Supplied with loading dye solution for sample DNA
Multi-panel gel images of FastRuler DNA Ladders


FastRuler DNA Ladders selection guide


Express DNA Ladders

Product photo, Two tubes and a package box of Express DNA ladders

When you need your gel results even faster, our GeneRuler Express DNA ladder is ready to withstand higher voltages, suboptimal gel percentages, and re-used running buffers. If you're looking for a broad-range, high-density DNA ladder for DNA mapping, the ZipRuler Express DNA ladder is supplied split in two ladders that are run in two neighboring gel lanes to separate faster and to provide plenty of information for accurate DNA sizing. Finally, if you need a robust ladder that is also useful for providing DNA quantification, choose one of our MassRuler Express ladders.

Features of express DNA ladders

  • Designed for faster separation
  • Formulated to withstand variation in electrophoresis conditions
  • Sharp bands, bright reference bands
  • Ready-to-use ladders stable for six months at room temperature
  • Supplied with loading dye for sample DNA
Multi-panel gel images of Express DNA Ladders

ZipRuler Express DNA Ladder Set

The Thermo Scientific ZipRuler Express DNA Ladder Set contains two ladders: ZipRuler Express DNA Ladder 1 and ZipRuler Express DNA Ladder 2. Both are mixtures of chromatography-purified individual DNA fragments. ZipRuler Express DNA Ladder 1 is premixed with the 6X Orange DNA Loading Dye (orange G and xylene cyanol), and ZipRuler Express DNA Ladder 2 is premixed with the 6X MassRuler DNA Loading Dye (bromophenol blue).

The set is designed for fast and accurate sizing of a broad range of DNA fragments and is compatible with various electrophoresis conditions. For fast separation, the two ladders are loaded into two different wells of the same gel. For longer runs, equal amounts of both ladders are loaded into the same gel well.

Also see standard-formulation GeneRuler Ladders and MassRuler Ladders.


Express DNA ladders selection guide


O’RangeRuler DNA Ladders

Product photo. 2 tubes of O’RangeRuler DNA ladders

O'RangeRuler DNA Ladders are step ladders that consist of basic unit repeats of 10, 15, 20, 50, 100, 200, or 500 bp. The ladders have a higher density of bands at a specific DNA size range and therefore are suitable for more accurate sizing of DNA in agarose or non-denaturing polyacrylamide gels.

Features of O’RangeRuler DNA Ladders

  • Step ladders—Ligation products of DNA fragments of equal increments
  • Sharp bands, evenly spaced reference bands
  • Ready-to-use—Premixed with loading dye for direct loading
  • Room temperature storage
  • Supplied with loading dye for sample DNA
Multi-panel gel images of O’RangeRuler DNA Ladders


O'RangeRuler DNA Ladders selection guide


Conventional DNA markers: Lambda, phage, and plasmid DNA ladders

Product photo Lambda DNA/EcoRI Marker

The Thermo Scientific conventional DNA markers are traditional molecular weight standards used for sizing and approximate quantification of linear double-stranded DNA fragments in agarose and non-denaturing polyacrylamide gels. The markers are composed of lambda, phage, or plasmid DNA digested to completion with the appropriate restriction enzyme(s), purified, and dissolved in storage buffer. The DNA fragments contain blunt or sticky ends depending on the restriction enzyme used for the marker’s preparation.

Features of lambda, phage, and plasmid DNA markers

  • Sizing and approximate quantification of DNA fragments
  • Sharp bands
  • Ready-to-use versions—Premixed with 6X DNA Loading Dye
  • Supplied with loading dye for sample DNA
lambda-phage-plasmid-gel-panels


Lambda, phage, and plasmid DNA markers selection guide


NoLimits DNA Fragments

Individual, highly purified DNA fragments, useful for researchers wanting to create custom ladders.

Learn more about NoLimits DNA Ladders


DNA electrophoresis resources

Explore other products for DNA electrophoresis workflow.

Access webinars, videos, articles, and other resources on standard molecular biology techniques from the Thermo Scientific Library.

Learn about gel electrophoresis basics, workflow, considerations, applications, and troubleshooting in separation and analysis of nucleic acids.

Support

Browse tips, troubleshooting help, and resources to optimize nucleic acid gel electrophoresis experiments.

Email or call our technical application scientists for additional questions regarding DNA ladders.

Stylesheet for Classic Wide Template adjustments

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