🦠microbiology review

DNA ladder

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

A DNA ladder is a molecular weight marker used in gel electrophoresis to estimate the size of DNA fragments. It consists of DNA fragments of known lengths.

5 Must Know Facts For Your Next Test

  1. DNA ladders are essential for determining the size of unknown DNA fragments during gel electrophoresis.
  2. They typically contain a range of fragment sizes, often from 100 base pairs to several kilobases.
  3. The bands created by a DNA ladder can be compared to experimental samples to estimate their molecular weights.
  4. DNA ladders are commercially available and can be customized for specific applications in molecular biology.
  5. They are often stained with ethidium bromide or other DNA-binding dyes for visualization under UV light.

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