<p><code>ORF1ab:4588I</code> corresponds to <code>ORF1b:187I</code> so one needs to subtract <code>4401</code> to go from <code>1ab</code> to <code>1b</code> and add <code>4401</code> to go the other way.</p>

CC BY-SA 4.0
2022-02-28T06:49:00.180Z
Just for clarification: 1a or 1b? You reference 1b in the question but answer with 1a.
KeyboardCat
CC BY-SA 4.0
2022-02-28T13:33:38.670Z
You're right, I fixed it, thanks!
Cornelius Roemer
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2021-10-15T13:59:03.590Z
2022-02-28T13:33:29.513Z
2022-02-28T13:33:29.513Z
Cornelius Roemer
<p>There is now an Open Source online tool that does the conversion, <a href="https://codon2nucleotide.theo.io/" rel="nofollow noreferrer">Codon2Nucleotide</a> by Theo Sanderson.</p>

CC BY-SA 4.0
2022-11-28T16:25:43.773Z
2022-11-28T16:25:43.773Z
Sir Cornflakes
<p>Some websites mention amino acid mutations as ORF1ab, most however use ORF1a/b instead.</p>
<p>So how can I translate from one to the other? What do I need to subtract from say <code>ORF1ab:4588I</code> to get the corresponding <code>N</code> in <code>ORF1b:&lt;N&gt;I</code>?</p>

<sars-cov-2><covid-19><codon><nomenclature><orf>
How to convert Sars-CoV-2 ORF1ab codon positions to ORF1b positions?
# How to convert Sars-CoV-2 ORF1ab codon positions to ORF1b positions?

(Asked by: username_0 on 2021-10-15)

Some websites mention amino acid mutations as ORF1ab, most however use ORF1a/b instead.

So how can I translate from one to the other? What do I need to subtract from say `ORF1ab:4588I` to get the corresponding `N` in `ORF1b:I`?

**Tags:** sars-cov-2, covid-19, codon, nomenclature, orf

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## 2 answers

### Answer by username_0 on 2021-10-15. Score: 2 | Accepted answer

`ORF1ab:4588I` corresponds to `ORF1b:187I` so one needs to subtract `4401` to go from `1ab` to `1b` and add `4401` to go the other way.

> **Comments:**
> **username_1**: Just for clarification: 1a or 1b? You reference 1b in the question but answer with 1a.  
> **username_0**: You're right, I fixed it, thanks!  

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### Answer by username_2 on 2022-11-28. Score: 2

There is now an Open Source online tool that does the conversion, [Codon2Nucleotide](https://codon2nucleotide.theo.io/) by Theo Sanderson.


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