200 Base Pair DNA Ladder Catalog # L-102


This ladder consists of 33 blunt end DNA bands at exactly 200 bp to 6,600 bp in 200 bp increments. The high intensity 1,000 bp band facilitates band identification. G+C content of the bands is 48%.

Quantity Supplied: 300 ul at 1 ul per loading
Storage Buffer: 10 mM Tris-HCl, 1 mM EDTA, pH 8.0 (TE buffer)
Store at: -20° C or below.

Repeated freeze-thaw cycles have no effect on this product. Vortex gently after thawing.

Recommended Use:

Make a ready to use working solution of the ladder in the tube labeled “Working Solution” as follows:

  • 200 ul 5X sample loading buffer (see Maniatis for formulation)
  • 750 ul TE buffer
  • 50 ul ladder stock solution

The working solution may be stored at 4° C for a few months. For longer term storage of the working solution, store at -20° C. Store the ladder stock solution at -20° C or below. Using the recommended working solution, a standard 20ul loading volume is sufficient for visualizing the bands by ethidium bromide staining after the gel run. Best results are obtained by filling wells completely. Each tube of ladder stock solution provides 300 loadings. Alternatively, load 1ul of the ladder stock solution.

Tips for Achieving the Best Results:

  • For best resolution from 200 bp to 2,000 bp, use 2.0% agarose. For best resolution from 1,000 bp to 6,600 bp, use 1.0% agarose. The user should determine empirically the optimal separation media and concentration for the user’s application.
  • To pinpoint the location of sample band re1ative to the ladder, try the following technique. Run three lanes in parallel: sample only, sample + ladder mix, ladder only. This technique is especially useful for bands above 2,000 bp.
  • Fill the gel well completely. A partially filled well may result in band smearing.
  • If the working solution will not be used for several weeks, store it in the freezer. Thaw the working solution completely before use.
  • Do not overload the unknown DNA sample. This will result in broad DNA bands, making precise determination of DNA fragment sizes difficult. If the DNA concentration is not known, consider loading dilutions of the unknown DNA sample.