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Error reading amino acid fasta file Win32 (Read 1492 times)
Filipe Garret
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Error reading amino acid fasta file Win32
Jun 14th, 2005 at 10:00am
 
Hi all,


Im having an issue with the latest version of Hyphy (0.99):
when reading amino acid data from a multi-fasta file the program recognizes it as if it were a nucleotide one.

But the same file converted to nexus by MEGA is correctly interpreted as aminoacid data.

The file I am having trouble is in:

http://161.116.70.61/other/pepito.fasta

Do you have any guess about what might be causing this problem?

Best regards,
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Sergei
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Re: Error reading amino acid fasta file Win32
Reply #1 - Jun 14th, 2005 at 10:06am
 
Dear Filipe,

Since FASTA does not provide a means to specify what type of data are present in the sequence file (NEXUS does, via the DATATYPE construct), HyPhy tries to make an educated guess about what the file contains. All files are assumed to be nucleotide by default, but if there are too many non ACGT characters (more than 50%), HyPhy assumes that the data are amino-acid sequences. This heuristic breaks down for very gappy alignments (which yours appears to be).

You can include the following HyPhy construct at the beginning of a FASTA/PHYLIP file to force the program to use the standard amino-acid alphabet:

Code:
$BASESET:BASE20

>seq1
...
>seq2
...
 



Alternatively, using the NEXUS format avoids the issue altogether.

HTH,
Sergei
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