Understand the relationship
The reasoning behind the result
Transcription is strand directional
template DNA 3′→5′ → mRNA 5′→3′
RNA polymerase reads a declared template in the antiparallel direction. A template stored 5′→3′ must therefore be reversed as well as complemented to obtain the mRNA written 5′→3′.
A coding strand already has the mRNA order, with thymine represented as uracil.
Coding and template strands are not synonyms
The coding DNA and mRNA share base order but are different polymers. The template is complementary and antiparallel.
The workbench labels all three records so a correct string is not detached from its strand meaning.
Ambiguity symbols preserve sets
IUPAC symbols such as R or Y represent sets of possible bases. Complementing swaps the corresponding sets rather than replacing uncertainty with N or choosing one base.
No probability is assigned within an ambiguity set.
A sequence transform is not an expression model
Introns, splice junctions, promoters, editing, transcription start sites and RNA processing are not inferred from the entered letters.
The output is a strand transformation, not evidence that the sequence is transcribed in a cell.
Follow the numbers
Transcribe a coding-strand record
- The entered coding DNA is 5′-ATGGCTTTCTAA-3′.
- Because it is already the coding strand, its order is retained.
- Each T is represented by U in the RNA polymer.
- The mRNA is 5′-AUGGCUUUCUAA-3′.
- The complementary template is displayed 3′-TACCGAAAGATT-5′ for reconciliation.
The three strings describe one declared strand relationship; no splicing or biological expression is inferred.
Quick guide
How to use this calculator
- Identify whether the supplied sequence is coding or template DNA before calculating.
- Choose the direction in which that sequence is written; direction changes the required reversal.
- Read the displayed coding, template and mRNA records together before using the sequence elsewhere.
Calculation method
Calculation and interpretation
Prevent a complement operation, strand reversal and T-to-U replacement from being mixed silently.
Coding input: mRNA(5′→3′) = coding DNA with T→U. Template input: mRNA is the antiparallel RNA complement, with reversal when the template is entered 5′→3′.
Worked example
Transcribe a coding-strand record
The three strings describe one declared strand relationship; no splicing or biological expression is inferred.
Coding input: mRNA(5′→3′) = coding DNA with T→U. Template input: mRNA is the antiparallel RNA complement, with reversal when the template is entered 5′→3′.
Supported inputs
Precision and limits
Declared strand required
The calculator cannot infer whether an unlabeled DNA string is coding or template.
One continuous record
One raw or single-record FASTA sequence is accepted; exon assembly and multi-record alignment are excluded.
IUPAC sets only
Ambiguity symbols are complemented as sets without choosing probabilities or bases.
No RNA processing
Introns, caps, poly(A), editing, promoters and transcript boundaries are not predicted.
Numerical support
The complete entered and derived records are retained for up to 10,000 DNA symbols.
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