Expression Technologies Inc.

DNA ladders/DNA markers for gel electrophoresis
1 kb, 1 kb plus, 100 bp, low range, high range quantitative DNA ladders or DNA markers

Product list of DNA ladders/DNA markers

How to select a DNA ladder/DNA marker... >

Features and benefits of DNA Ladders/DNA markers

Definition of DNA ladders/DNA markers

A DNA ladder usually contains a set of known DNA fragments with different sizes in base pairs (bp) or kilo bases (kb). These DNA fragments are separated and visualized as DNA bands on a gel. These separated DNA bands together look like a ladder on the gel (see pictures below) and therefore it is called DNA ladder. DNA ladders are used in gel electrophoresis to determine the size and quantity of testing DNA fragments of genomic, plasmid, and PCR DNA. Most DNA ladders are in liquid form. A few microliters of a DNA ladder is usually loaded on a gel with testing DNA fragments. The quantity of each DNA band is known once the loading volume is determined. After electrophoresis, the size and quantity of the testing DNA fragments may be determined by comparing with the size and quantity of the DNA bands in the DNA ladder. DNA ladders, DNA markers, nucleic acid ladders, and nucleic acid markers are interchangeable phrases. Some scientists may call them DNA standards or nucleic acid standards. The number before a DNA ladder indicates the size interval of the DNA fragments. For example, the sizes of the DNA fragments in a 100 bp DNA ladder are mostly separated by 100 bp and 1 kb DNA ladder contains most DNA fragments with 1 kb size difference. Some 100 bp DNA ladders have over 1 kb DNA fragments and some 1 kb ladders have many 100 bp DNA fragments.

Synonyms of DNA ladders/DNA markers

Plural: DNA ladders, DNA markers, DNA standards, nucleic acid ladders, nucleic acid markers, nucleic acid standards
Singular: DNA ladder, DNA marker, DNA standard, nucleic acid ladder, nucleic acid marker, nucleic acid standard

Note: DNA marker or DNA markers are also used in genetic, forensic, and disease analysis. The precise term for these definitions should be genetic marker or markers. These are unique DNA sequences which are indictors for certain genetic traits. These definitions are not related to the products described here. DNA standard or DNA standards are mainly used in DNA quantification by UV spectrometer. Our DNA ladders may be used in DNA quantification.

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QuantDNA50-15k^TM 1 kb DNA ladder/DNA marker (50 bp-15 kb)
1 kb or 1kb plus DNA ladder or DNA marker for quantification and sizing

QuantDNA50-15K^TM 1 kb DNA ladder is used for determining the size and mass of linear double-stranded DNA from 50 bp to 15 Kb. This DNA ladder has 16 bands from smallest 50 bp to largest 15 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 2 kb band which is 20 times of the lowest quantity DNA band of 100 bp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other 1 kb or 1 kb plus DNA ladders or 2 log DNA ladders. However it offers broader size range and accurate quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of QuantDNA50-15k^TM 1 kb DNA ladder/DNA marker

Real loading volumes of QuantDNA50-15k^TM 1 kb DNA ladder/DNA marker

The QuantDNA50-15K^TM 1 kb DNA ladder is loaded on 1% agarose TBE and run in 1X TBE. Both 50 and 100 bp fragments diffused during electrophoresis on 1% agarose at small loading volumes (1 ul and 2 ul). The diffusion will be reduced in higher percentage gels (>2%). Both 50 and 100 bp bands are clearly visible on these gels at 1 ul and 2 ul loadings.

Product literatures of QuantDNA50-15K^TM 1 kb DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of QuantDNA50-15K^TM 1 kb DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 8 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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QuantDNA50-2k^TM low range mass DNA ladder/DNA marker (50 bp-2 kb)
low range mass DNA ladder or DNA marker for quick separation, quantification, and sizing

QuantDNA50-2k^TM DNA ladder is used for determining the size and mass of linear double-stranded DNA from 50 bp to 2 Kb. This DNA ladder has 7 bands from smallest 50 bp to largest 2 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 2 kb band which is 20 times of the lowest quantity DNA band of 100 bp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other low range DNA mass ladders or 100 bp DNA mass ladders. However it offers accurate quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of QuantDNA50-2k^TM low range mass DNA ladder/DNA marker

The QuantDNA50-2k^TM DNA ladder is loaded on 2% agarose TBE and run in 1X TBE. The sizes of DNA fragments in base pairs are listed on the right of the picture. The quantities in nanograms of different loading volumes are indicated on the left of the figure.

Product literatures of QuantDNA50-2k^TM low range mass DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of QuantDNA50-2k^TM DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-base 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 2 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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QuantDNA1k-10k^TM high range mass DNA ladder/DNA marker (1 kp-10 kb)
high range mass DNA ladder or DNA marker for quick separation, quantification, and sizing

QuantDNA1k-10k^TM DNA ladder is used for determining the size and mass of linear double-stranded DNA from 1 kp to 10 Kb. This DNA ladder has 6 bands from smallest 1 kp to largest 10 kb. The quantity ratio of the DNA bands in the DNA ladder is 10 times. The highest quantity DNA band is the 10 kb band which is 10 times of the lowest quantity DNA band of 1 kp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. This DNA ladder is similar with other high range DNA mass ladders. However it offers accurate quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of QuantDNA1-10k^TM high range mass DNA ladder/DNA marker

The QuantDNA1-10K^TM DNA ladder is loaded on 1% agarose TBE and run in 1X TBE. The sizes of DNA fragments in base pairs are listed on the right of the picture. The quantities in nanograms of different loading volumes are indicated on the left of the figure.

Product literatures of QuantDNA1k-10k^TM DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of QuantDNA1-10K^TM DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 6 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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DigiDNA50-15k^TM 1 kb plus DNA ladder/DNA marker (50 bp-15 kb)
1 kb or 1kb plus DNA ladder or DNA marker for sizing and quantification

DigiDNA50-15K^TM 1 kb plus DNA ladder is used for determining the size and mass of linear double-stranded DNA from 50 bp to 15 Kb. This DNA ladder has 19 bands from smallest 50 bp to largest 15 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 2 kb band which is 20 times of the lowest quantity DNA band of 100 bp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other 1 kb plus DNA ladders or 2 log DNA ladders. However it offers broader size range and accurate quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of DigiDNA50-15k^TM 1 kb plus DNA ladder/DNA marker

Real loading volumes of DigiDNA50-15k^TM 1 kb plus DNA ladder/DNA marker

The DigiDNA50-15K^TM 1 kb plus DNA ladder is loaded on 1% agarose TBE and run in 1X TBE. Both 50 and 100 bp fragments diffused during electrophoresis on 1% agarose at small loading volumes (1 ul and 2 ul). The diffusion will be reduced in higher percentage gels (>2%). Both 50 and 100 bp bands are clearly visible on these gels at 1 ul and 2 ul loadings.

Product literatures of DigiDNA50-15K^TM 1 kb plus DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of DigiDNA50-15K^TM 1 kb plus DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 11 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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DigiDNA50-2k^TM 100 bp DNA ladder/DNA marker (50 bp-2 kb)
100 bp or low range DNA ladder or DNA marker for sizing and quantification

DigiDNA50-15K^TM 100 bp DNA ladder is used for determining the size and mass of linear double-stranded DNA from 50 bp to 2 Kb. This DNA ladder has 11 bands from smallest 50 bp to largest 2 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 2 kb band which is 20 times of the lowest quantity DNA band of 100 bp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other 100 bp or low range DNA ladders. However it offers accurate DNA quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of DigiDNA50-2k^TM 100 bp DNA ladder/DNA marker

The DigiDNA50-15K^TM 100 bp DNA ladder is loaded on 2% agarose TBE and run in 1X TBE. The sizes of DNA fragments in base pairs are listed on the right of the picture. The quantities in nanograms of different loading volumes are indicated on the left of the figure.

Product literatures of DigiDNA50-2k^TM 100 bp DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of DigiDNA50-2k^TM 100 bp DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 3 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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DigiDNA1-15k^TM 1 kb DNA ladder/DNA marker (1 kb-15 kb)
high range or 1 kb DNA ladder or DNA marker for sizing and quantification

DigiDNA50-15K^TM 1 kb DNA ladder is used for determining the size and mass of linear double-stranded DNA from 1kb to 15 Kb. This DNA ladder has 10 bands from smallest 1 kb to largest 15 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 10 kb and 5 kb bands which are 20 times of the lowest quantity DNA band of 1 kb. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other high range DNA ladders. However it offers accurate DNA quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of DigiDNA1k-15k^TM 1 kb DNA ladder/DNA marker

The DigiDNA1k-15K^TM DNA ladder is loaded on 1% agarose TBE and run in 1X TBE. The sizes of DNA fragments in base pairs are listed on the right of the picture. The quantities in nanograms of different loading volumes are indicated on the left of the figure.

Product literatures of DigiDNA1k-15K^TM 1 kb DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of DigiDNA1k-15K^TM 1 kb DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 10 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

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FastRun50-15k^TM 1 kb DNA ladder/DNA marker (50 bp-15 kb)
broad range, 2 log, or 1 kb DNA ladder or DNA marker for quick separation, quantification, and sizing

FastRun50-15K^TM 1 kb DNA ladder is used for determining the size and mass of linear double-stranded DNA from 50 bp to 15 Kb. This DNA ladder has 12 bands from smallest 50 bp to largest 15 kb. The quantity ratio of the DNA bands in the DNA ladder is 20 times. The highest quantity DNA band is the 2 kb band which is 20 times of the lowest quantity DNA band of 100 bp. DNA size and quantity can be accurately determined by comparing relative positions and staining intensities of the DNA bands. It is commonly used in the studies of plasmid DNA and PCR products. It is similar with other 1 kb, 2 log, or broad range DNA ladders. However it offers fewer DNA bands for quick separation and accurate DNA quantification. All these DNA ladders/DNA markers are ready-to-use. No extra dyes or loading  buffers are needed.

Recommended loading volume of this DNA ladder/DNA marker: 5 ul/lane.                       

Picture of FastRun50-15k^TM 1 kb DNA ladder/DNA marker

The FastRunDNA50-15K^TM 1 kb DNA ladder is loaded on 1% agarose TBE and run in 1X TBE. The sizes of DNA fragments in base pairs are listed on the right of the picture. The quantities in nanograms of different loading volumes are indicated on the left of the figure.

Product literatures of FastRun50-15K^TM 1 kb DNA ladder/DNA marker in PDF files

Technical sheet I MSDS

Size and quantity of each DNA band of FastRun50-15K^TM 1kb DNA ladder/DNA marker at 5 ul loading

The exact length of each DNA band in base pairs is listed in the table. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments and do not affect the migration properties of the DNA bands. The actual size of each DNA fragment runs at the apparent size on a agarose gel or a polyacrylamide gel including a sequencing gel. Since each DNA fragment has 4-bases 5' overhangs at both ends, its migration property on a gel is indistinguishable from a blunt end DNA fragment of same molecular weight. For example DNA band # 7 migrate exactly same as an 1 kb blunt end DNA fragment on an agarose gel.

FastRun^TM50-15k DNA standard is used for determining the size and mass of linear double-stranded DNA from 50 bp to 15 Kb. It has 12 well-separated DNA bands. Running this DNA standard at 300 v for 10 to 15 minutes is sufficient to distinguish these DNA bands on a regular agarose gel. The agarose gel will not melt because of short running time. QuantDNA^TM50-15k DNA standard has twice as many DNA bands from 50 bp to 2 kb. DigiDNA^TM50-15k is similar as QuantDNA^TM50-15k except that it has more DNA bands from 2 kb to 15 kb while its high molecular weight DNA (>2kb) have same quantity. DigiDNA^TM50-2k and QuantDNA^TM50-2k are used for low molecular weight DNA. DigiDNA^TM1k-15k and QuantDNA^TM1k-15k are used for high molecular weight DNA. The 2 kb band of all these DNA standards contains the most DNA and therefore serves as an indicator band. All of these DNA standards can be used to accurately determine the size (in base pairs) and quantity (in nanograms) of a DNA sample. The actual mass of each DNA band may vary in each lot. The exact length of each DNA band in base pairs is 4 base pairs less than it is indicated on the picture. Each DNA fragment contains 4 base single strand 5' overhangs at both ends. These overhangs allow convenient labeling of these DNA fragments.

Information about DNA ladders/DNA markers

Storage conditions of DNA ladders/DNA markers

All of our DNA ladders/DNA markers are stable for six months at room temperature (25 ⁰C), one year at 4 ⁰C, or more than two years at - 20 ⁰C. After extended storage, the DNA ladders/markers should be mixed well before use.

We recommend to store these DNA ladders/DNA markers at 4 ⁰C for normal uses.

All of our DNA ladders/DNA markers are shipped at ambient temperature.

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How to select a DNA ladder/DNA marker for an application

1. Size range:
   a). Size range: the smallest and largest DNA bands in a DNA ladder/DNA marker determine its size range. The testing DNA fragments should be in this range.
   b). Number of DNA bands: the number of DNA bands in a DNA ladder/DNA marker determines the accuracy of sizing of the testing DNA fragments. The size of testing DNA fragments can be determined more accurately with more bands in a DNA ladder/DNA marker. However more DNA bands make it difficult to be separated completely in a short electrophoresis time. Therefore in a quick run, less DNA bands in a DNA ladder/DNA marker is preferred.
   Most scientists select their DNA ladders/DNA markers based on size range first. For example, QuantDNA50-2k DNA ladder/DNA marker will be selected if the testing DNA size is from 50 bp to 2 kb and QuantDNA50-15k DNA ladder/DNA marker will be selected if the testing DNA size is from 50 bp to 15 kb. When more DNA bands are desired, DigiDNA^TM DNA ladders/DNA markers will be selected. When less DNA bands are sufficient, FastRun50-15k^TM DNA ladder/DNA marker may be used.

2. Quantity feature:
   a). Gradient of quantity: Allow accurate quantification of DNA fragments.
   b). Discontinuous Quantity: Allow rough quantity estimation of DNA fragments.
   All of our DNA ladders/DNA markers have gradients of quantity and can be used to accurately estimate DNA quantity regardless the size of the testing DNA. Extensive affords have been made to ensure its quantity accuracy. Quantification on the gel can save significant amount of time and labor than UV reading especially when many DNA samples are tested. Quantification using our DNA ladders/DNA markers is more accurate than UV reading. This is simply because of contamination of testing DNA sample with impurities including but not limited to RNA, protein, oligos, or nucleotides. UV reading will include these contaminants and will over estimate the DNA quantity.

3. Both size range and quantity feature.

4. Cost: Dividing the price by number of loadings is the cost of the DNA ladder/DNA marker. Recommended loading volume is normally larger than the minimum loading volume may be used. The minimum loading volume of our DNA ladders/DNA markers is one microliter on a regular agarose gel. A certain loading volume is needed when a specific quantity or quantity range is desired.

Range, bands, and quantity of DNA ladders/DNA markers

FAQs about DNA ladders/DNA markers

1. How to determine the size and quantity of  a DNA sample with these DNA ladders/DNA markers?
2. How much should each DNA ladder/DNA marker be loaded on an agarose gel?
3. How accurate is the quantity determination by these DNA ladders/DNA markers?
4. Can we use a density scanner to determine quantity with these DNA ladders/DNA markers?
5. Can we use these DNA ladders/DNA markers on buffer-less gel?
6. Why are low or high molecular weight (MW) DNA bands of these DNA ladders/DNA markers sometimes not resolved or detected?
7. Can we label the DNA fragments of the DNA ladders/DNA markers?
8. Why do we need to know the quantity of a DNA sample?

References of DNA ladders/DNA markers

1. DNA ladder defined by Wikipedia.
2. DNA markers defined by Medical Dictionary.
3. Genetic marker defined by Wikipedia.

Price list of DNA ladders/DNA markers

Warranty of DNA ladders/DNA markers

The descriptions of our DNA ladders/DNA markers on this pages and other related pages are the specifications of our products. We guarantee that each of these DNA ladders/DNA markers meets its specifications. If these DNA ladders/DNA markers fail to meet such specifications, Expression Technologies Inc. will promptly replace the products. All products need to be shipped back to us before replacement.
Size guarantee: Each DNA fragment of these DNA ladders/DNA markers migrates exactly at its apparent size as a blunt end fragment.
Quantity guarantee: Each DNA fragment of these DNA ladders/DNA markers is within 10% of its specified quantity if it is stored at 4 ⁰C or less for one year from the date of purchase.
Loading guarantee: The picture of a gel with 1 or 2 ul loading volumes will be similar as presented above for QuantDNA50-15k^TM and DigiDNA50-15k^TM 1 kb DNA ladders/DNA markers.
Stability guarantee: All of our DNA ladders/DNA markers are stable for six months at room temperature (25 ⁰C), one year at 4 ⁰C, or more than two years at - 20 ⁰C.
General product warranty also applies to these DNA ladders/DNA markers.

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