| More docs on the ARB website. See also index of helppages. Last update on 14. Feb 2019 .

Main topics:

- ARB: a Short Introduction
- Glossary

Related topics:

- Translate DNA to Protein

# Realign DNA

- OCCURRENCE
- DESCRIPTION
- NOTES
- EXAMPLES
- WARNINGS
- BUGS

## OCCURRENCE

### ARB_NT/Sequence/Align sequences/Realign nucleic acid according to aligned protein

## DESCRIPTION

### If you have translated DNA sequences into protein sequences and then have aligned the resulting protein sequences, this function can be used to re-align the DNA sequences according to the (modified) protein alignment.

### Simply select the protein and the corresponding DNA alignment and press 'REALIGN' to re-align the DNA sequences of all marked species.

## NOTES

### If the species contains a field 'transl_table' (which should contain the translation table number as used by the EMBL database) it is used to detect the correct translation table. If no such field is defined a translation-table-auto-detection takes place.

### If the species contains a field 'codon_start' it is overwritten with '1' to make further translations work properly.

### Either both fields ('transl_table' and 'codon_start') or none of them has to exist. Otherwise an error occurs and you have to correct these fields manually (e.g. by using the search tool and 'Write to fields of listed' or by deleting these fields).

### After sucessful re-alignment the field 'codon_start' will be set to '1' if

- it already existed before or
- if ARB was able to strictly determine a content for the field 'transl_table', which will be set then.

### If the re-alignment was possible using two or more different translation tables neighter 'transl_table' nor 'codon_start' will be written.

## EXAMPLES

### None

## WARNINGS

### If you have single DNA bases at the beginning (or end) of the DNA sequence there have to be corresponding proteins in the protein sequence. Otherwise translation will fail.

### Normally, if you use codon start other than 1 during translation, a 'X' will be inserted into the resulting protein sequence. That X is required by the re-aligner to skip up to 3 DNA positions, while it is trying to find the correct ORF.

### Missing X's at protein sequence start are a very common cause, for various kinds of error messages from the re-aligner.

## BUGS

### No bugs known