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Nucleic Acid Electrophoresis
 
Agarose and Acrylamide | Dyes, Loading Buffers, and Nucleic Acid Gel Stains | Markers and Ladders | Running Buffers | Equipment and Accessories

Markers and Ladders

  Nucleic Acid Markers
Nucleic Acid Markers: DNA Ladder Markers
DNA Ladder Markers

Nucleic Acid Markers

Agarose and polyacrylamide gel electrophoresis are two common techniques for determining the size, the purity and sequence identity (e.g. Northern and Southern blots) of nucleic acids. Nucleic acids can be visualized on gels using fluorescent stains (e.g. Ethidium bromide or SYBR® Green) or by silver staining. DNA sequences can also be visualized by hybridization using labeled probes on Northern or Southern blots. Size markers are necessary to help identify the size of the unknown nucleic acid and verify the separation and staining efficiency on the gel. A wide selection of nucleic acid markers for every size and application are available. Each marker comes with a Product Information sheet containing information on the product and how to use it.


Marker(s) Product # Ladder Image No. of Bands Smallest Fragment Largest Fragment Suggested Agarose Conc. %
DNA Ladder Markers     Base pairs Base pairs  
PCR 20 bp low ladder P1598 Image 50 20 1000 2.5
PCR 100 bp low ladder P1473 Image 10 100 1000 2.0
PCR 100 bp low ladder (DirectLoad) D3687 Image 10 100 1000 2.0
PCR Low ladder Set D7808 Image 10 & 50 20 1000 2.5
PCR Marker P9577 Image 8 50 2000 2.0
50 bp StepLadder S7025 Image 17 50 3000 1.5
50 bp ladder (DirectLoad) D3812 Image 17 50 3000 1.5
123 bp ladder D5042 Image 34 123 4182 1.5
Wide range DNA marker (DirectLoad) D7058 Image 16 50 10,000 0.75 - 2.0
1 kb ladder D0428 Image 11 500 10,000 0.75
1 kb ladder (DirectLoad) D3937   11 500 10,000 0.75
Supercoiled DNA ladder D5292 Image 11 2067 16,210 0.7
ChromaTrack Dye Marker     Base pairs Base pairs  
ChromaTrack Dye Marker C8468 Image 6 Variable Variable Variable
DNA Digest Markers     Base pairs Base pairs  
pBR322 Hae III digest D9655 Image 22 8   2.5
pUC18 Hae III digest D6293 Image 11 11   2.5
pUC18 Mspl digest D4797 Image 13 26   2.5
θX174 Hae III digest D0672 Image 11 72   2.0
λ DNA BstE digest D9793 Image 14 117   1.0
λ DNA Pst I digest D1793 Image 29 15   0.7
λ DNA EcoR1 and Hind III digest D9281 Image 13 125   0.7
λ DNA Hind III digest D9780 Image 8 125   0.75
λ DNA EcoR1 digest D5282 Image 6 3530   0.7

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Nucleic Acid Markers: DNA Ladder Markers

Marker(s) Product # Ladder Image No. of Bands Smallest Fragment Largest Fragment Suggested Agarose Conc. %
DNA Ladder Markers     Base pairs Base pairs  
λ DNA BstE digest D2916 Image 10 1503 48,502 0.4
RNA Markers     Bases Bases  
5S Ribosomal RNA marker R8385   1     1.25
0.1 - 1 kb RNA marker R6895 Image 7 100 1000 1.25
18S and 28S Ribosomal RNA marker R0889 Image 2 2000 5300 1.0
0.28 - 6.6 kb RNA marker R7644 Image 9 281 6583 1.0
0.36 –9.5 kb RNA marker R3137   8 360 9490 1.0
0.2 – 10 kb RNA marker R7020 Image 9 200 10,000 1.0
Pulsed-Field DNA Markers     Kilobase pairs Kilobase pairs  
0.1 – 200 kb Pulse marker D2291 Image 12 0.1 194 1.0
50 – 1000 kb Pulse marker D2416 Image 16 48.5 1018.5 1.0
225 – 2200 kb Pulse marker D4658 Image 21 225 2200 1.0

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DNA Ladder Markers

The DNA ladder markers are created as evenly spaced (ladder) repeats. Half of these markers are especially designed for the analysis of PCR products. The PCR DNA markers range from 20 bp to 1000 bp, a common range of PCR generated DNA fragments. The banding pattern of PCR DNA markers is more closely spaced for more accurate determination of the size of the PCR product. If a larger range is necessary, Sigma's 50 bp ladder (S7025) or the 1 kb ladder (D0428) may be more appropriate.


Fragment Size/Number PCR 20bp PCR 100bp Direct Load PCR 100bp PCR Marker Step Ladder 50bp Direct Load 50bp 123 bp Direct Load Wide Range 1 kb Direct Load 1kb
  P1598 P1473 D3687 P9577 S7025 D3812 D5042 D7058 D0428 D3937
Ladder Image Image Image Image Image Image Image Image Image Image  
Fragment Size →
Number↓		 bp bp bp bp bp bp bp bp bp bp
1 1000 1000 1000 2000 3000 3000 4182 10,000 10,000 10,000
2 980 900 900 1500 2000 2000 4059 8000 8000 8000
3 960 800 800 1000 1000 1000 3936 6000 6000 6000
4 940 700 700 750 900 900 3813 5000 5000 5000
5 920 600 600 500 800 800 3690 4000 4000 4000
6 900 500 500 300 700 700 3567 3000 3000 3000
7 880 400 400 150 600 600 3444 2500 2500 2500
8 860 300 300 50 500 500 3321 2000 2000 2000
9 840 200 200   450 450 3198 1550 1500 1500
10 820 100 100   400 400 3075 1400 1000 1000
11 800       350 350 2952 1000 500 500
12 780       300 300 2829 750    
13 760       250 250 2706 500    
14 740       200 200 2583 400    
15 720       150 150 2460 300    
16 700       100 100 2337 200    
  Every 20 bp to.       50 50 Every 123bp to. 100    
34             123 50    
  40                  
50 20                  

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