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Markers and Ladders Selection Guide

Find more protocols and selection guides in the Molecular Biology Guide.

 Introduction

DNA and RNA size markers contain a mixture of DNA (or RNA) fragments of known length, making them suitable for estimating the fragment length of concurrently run samples. They stain well with ethidium bromide and other common nucleic acid stains for visualization after gel electrophoresis. For more information and background, please visit the Introduction to Markers and Ladders.

Sigma-Aldrich offers  a variety of markers for nucleic acid size determination of sample separated by various gel electrophoresis methods.

Click on image for larger view.


 Standard DNA Markers

Agarose gel electrophoresis requires standard DNA markers. Sigma has markers in three sizes, also available in a convenient, ready-to-use DirectLoad™ version:

D3812 –
DirectLoad™ Step Ladder,
50 bp
S7025 –
Step Ladder,
50 bp
D7058 –
DirectLoad™ Wide Range DNA Marker
D5042 –
123 bp Ladder
D3937 –
DirectLoad™ 1 kb DNA Ladder
D0428 –
1 kb Ladder
50-3,000 bp 50-3,000 bp 50-10,000 bp
123-4,182 bp
500-10,000 bp
500-10,000 bp
Add to Cart
Add to Cart
Add to Cart
Add to Cart
Add to Cart
Add to Cart

 Digested DNA Markers

Agarose gel electrophoresis for size determination of DNA digest fragments benefits from markers prepared as fragments of digested DNA. Sigma has seven DNA digest marker choices:

D9655 –
pBR322 Hae III Digest
D0672 –
φX174 DNA Marker Hae III Digest
D6293 –
pUC18 DNA Hae III Digest
D9780 –
Lambda DNA Hind III Digest
D9281 –
Lambda DNA EcoR I Hind III Digest
D2916 –
Lambda DNA Mixed Digest
D5282 –
Lambda DNA EcoR I Digest
8-587 72-1,353 80-587 564-23,130 564-21,226 1,053-48,505 3,530-21,226
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Add to Cart
Add to Cart
Add to Cart
Add to Cart
Add to
Cart
Add to Cart

 PCR Markers

Agarose or polyacrylamide gel electrophoresis for size determination of PCR fragments benefits from markers designed for use with PCR fragments. Sigma has four PCR marker choices:

P1598 –
PCR 20 bp
Low Ladder

D3687 –
DirectLoad™ PCR
100 bp Low Ladder

P1473 –
PCR 100 bp
Low Ladder

P9577 –
PCR Marker

20-1,000 bp 100-1,000 bp 100-1,000 bp 50-2,000 bp
Add to Cart
Add to Cart
Add to Cart
Add to Cart

 RNA Markers

RNA electrophoresis requires markers prepared from RNA, like these two choices:

R7020 –
Transcript RNA Markers
0.2-10 kb
R7644 –
Transcript RNA Markers
0.28-6.6 kb
Add to Cart
Add to Cart