Genuler 1kb DNA Ladder from Sigma-Aldrich is a precision size marker designed for routine agarose gel analysis. Engineered with high-quality DNA fragments at 100 bp intervals, it supports reliable band visualization and accurate sizing of PCR products and restriction digests.
This ladder delivers consistent performance across multiple experiments, making it suitable for both teaching labs and research workflows. The following sections detail its specifications, applications, handling, and practical guidance for daily use.
| Product Name | Genuler 1kb DNA Ladder | Sigma-Aldrich Catalog | Typical Concentration |
|---|---|---|---|
| Formulation | DNA fragments in TE buffer | — | ~50 ng/μL per band |
| Size Range | 100 bp to 1000 bp | — | — |
| Fragment Intervals | Every 100 bp | — | — |
| Gel Compatibility | 1–2% agarose | — | — |
| Storage | 4°C | Sigma-Aldrich Ref 11420243 | Ready-to-use |
| Applications | PCR sizing, restriction checks | — | — |
| Visualization | EB or safe dyes, clear bands | — | — |
Key Product Specifications and Features
Performance and Format
The Genuler 1kb DNA Ladder provides sharp, evenly spaced bands from 100 bp to 1000 bp. Each fragment is synthesized and quality-controlled to ensure consistent mobility across agarose gels. The ladder is supplied in a ready-to-use format that requires no additional mixing or dilution before loading.
Recommended Running Conditions
For optimal resolution, run the ladder at 80–100 V in 1–2% agarose gels with TAE or TBE buffer. Shorter run times preserve band clarity, while longer runs may cause band spreading at the bottom of the gel. Standard ethidium bromide or SYBR Safe staining provides sufficient sensitivity for visualization.
Applications in Molecular Biology Workflows
PCR Product Sizing
Researchers use the Genuler 1kb DNA Ladder to confirm the expected size of PCR amplicons. The 100 bp interval spacing allows precise estimation of product length, which is essential for cloning, genotyping, and diagnostics.
Restriction Digestion Verification
The ladder also serves as a reliable size reference when assessing enzyme digestion outcomes. By comparing band patterns of digested samples against the ladder, users can quickly verify complete or partial cleavage events.
Handling, Storage, and Troubleshooting
Storage and Stability
Store the ladder at 4°C as supplied. For long-term preservation, aliquot and freeze at −20°C, avoiding repeated freeze-thaw cycles. Proper storage maintains band integrity and ensures consistent performance across experiments.
Troubleshooting Common Issues
If band sharpness decreases, check gel concentration and running voltage. Smiling bands often result from uneven agarose casting or thermal gradients during electrophoresis. Verify buffer freshness and ensure uniform staining to achieve reproducible results.
Best Practices and Recommendations
- Verify ladder band positions against a known marker during initial use.
- Use fresh buffer and appropriately cast agarose gels for consistent migration.
- Load the ladder in the well closest to the positive electrode to monitor front-running effects.
- Document imaging conditions to enable reliable comparisons across experiments.
FAQ
Reader questions
How many reactions can one vial cover?
A single vial of Genuler 1kb DNA Ladder is sufficient for approximately 20–30 standard gel loadings, depending on sample volume and staining intensity requirements.
Can this ladder be used in native gels?
Yes, the ladder is compatible with native polyacrylamide and agarose gels, though migration may vary with buffer composition and gel percentage.
Is the DNA in the ladder degraded by nucleases?
The fragments are designed for enhanced resistance to nuclease activity under standard storage conditions, but long-term exposure to ambient temperatures should be avoided.
Are there alternatives for smaller size increments?
For resolutions below 100 bp, consider specialized ladders with 10–50 bp intervals; the Genuler 1kb ladder remains ideal for routine 100 bp increment checks.