The coding strand of a DNA double helix is the strand not used as a template by DNA or RNA polymerase during DNA replication or RNA transcription.
However, because the replicated/transcribed nucleic acidis produced from the template strand of DNA based on complementarity, it winds up being identical to the coding strand (except for the replacement of thymine with uracil in the case of RNA). See the figure below for a simplified depiction of the coding and template strands in the case of RNA transcription.
