obtaining sequence names after local blast

[cdes79]

Dear all,

i am trying to create an annotation for a custom array of a non-model species. I am running the latest version of BLAST+ (2.2.29+) and using the blastx. My output does not contain the gene names and i would like to have those.

I know this topic has been covered in a previous thread (http://seqanswers.com/forums/showthread.php?t=14031) and that it is not possible to obtain gene informations using blast+.

I am wondering if there are alternative ways by which other people achieve this tasks (i am not keen in using blast2GO as it runs very slowly). I would appreciate some hints.

[rhinoceros]

The manual. You could try e.g. the stitle (subject title) flag. Alternatively, it shouldn't be very hard to link subject gi's or accessions to other information with entrez direct..

[cdes79]

Thanks rhinoceros,

i was looking at the options via the blastx -help on the terminal and it does not have that stitle flag amongst the options for some reasons. I am certainly trying that.

Also thanks for the entrez direct, i wasnt aware of it. I am new to blast and in general new to bioinformatics so i apologize if the question was very basic. I guess we all ahve to start somewhere. :-)

[rhinoceros]

Thanks rhinoceros,
i was looking at the options via the blastx -help on the terminal and it does not have that stitle flag amongst the options for some reasons. I am certainly trying that.

It's an option within -outfmt, e.g. -outfmt '6 std stitle' gives you the standard tabular output + stitle as the last column.

[cdes79]

It's an option within -outfmt, e.g. -outfmt '6 std stitle' gives you the standard tabular output + stitle as the last column.

i know, i read the terminal manual. But again it is not there. Pasted below the relevant section. Anyway, i am running it as we speak and it is running fine. I'll see the output when it comes out.

*** Formatting options
-outfmt <String>
alignment view options:
0 = pairwise,
1 = query-anchored showing identities,
2 = query-anchored no identities,
3 = flat query-anchored, show identities,
4 = flat query-anchored, no identities,
5 = XML Blast output,
6 = tabular,
7 = tabular with comment lines,
8 = Text ASN.1,
9 = Binary ASN.1,
10 = Comma-separated values,
11 = BLAST archive format (ASN.1)

Options 6, 7, and 10 can be additionally configured to produce
a custom format specified by space delimited format specifiers.
The supported format specifiers are:
qseqid means Query Seq-id
qgi means Query GI
qacc means Query accesion
qaccver means Query accesion.version
qlen means Query sequence length
sseqid means Subject Seq-id
sallseqid means All subject Seq-id(s), separated by a ';'
sgi means Subject GI
sallgi means All subject GIs
sacc means Subject accession
saccver means Subject accession.version
sallacc means All subject accessions
slen means Subject sequence length
qstart means Start of alignment in query
qend means End of alignment in query
sstart means Start of alignment in subject
send means End of alignment in subject
qseq means Aligned part of query sequence
sseq means Aligned part of subject sequence
evalue means Expect value
bitscore means Bit score
score means Raw score
length means Alignment length
pident means Percentage of identical matches
nident means Number of identical matches
mismatch means Number of mismatches
positive means Number of positive-scoring matches
gapopen means Number of gap openings
gaps means Total number of gaps
ppos means Percentage of positive-scoring matches
frames means Query and subject frames separated by a '/'
qframe means Query frame
sframe means Subject frame
btop means Blast traceback operations (BTOP)
When not provided, the default value is:
'qseqid sseqid pident length mismatch gapopen qstart qend sstart send
evalue bitscore', which is equivalent to the keyword 'std'
Default = `0'

[Birdman]

Just use the XML output (outfmt -5) and parse it to obtain gene names.

[westerman]

@cdes76: You need a more recent version of blast. Mine is blastx: 2.2.29+
Package: blast 2.2.29, build Dec 10 2013 14:41:40 and has 'stitle' in it.

@Birdman: IMHO parsing XML is not that easy. Oh, you and I can do it but the casual user will have more problems. Did you see the recent note from NCBI saying that they want input on how to make their XML more standard/parsable?

[cdes79]

@cdes76: You need a more recent version of blast. Mine is blastx: 2.2.29+
Package: blast 2.2.29, build Dec 10 2013 14:41:40 and has 'stitle' in it.

@Birdman: IMHO parsing XML is not that easy. Oh, you and I can do it but the casual user will have more problems. Did you see the recent note from NCBI saying that they want input on how to make their XML more standard/parsable?

thanks westerman for the support, i think it is easy to forget how daunting this field can be, particularly for people that are not dedicated bioinformaticians, but biologists trying to use new tools. Anyway, back to us i think i figured what the problem might be. I said before i could not find the "stitle" and actually when i used it did not add the sequence info to the output.

Then i noticed that although i installed the latest version 2.2.29+ when i go blastx -h it tells me in the description that i have 2.2.25+. I had a previous blast version installed and probably that is why i am experiencing the problem.

I am now running the command giving the path to the right blastx and see what happens (it is running now). Do you know how i can fix this problem and make sure the blastx runs from the right folder? I assume i should change the PATH? How so?

Thanks, Christian

[westerman]

I am now running the command giving the path to the right blastx and see what happens (it is running now). Do you know how i can fix this problem and make sure the blastx runs from the right folder? I assume i should change the PATH? How so?

Changing the PATH is a good idea. I am sure there are many tutorials on how to do so out there. In general, from Bash,

export PATH=/new/path:$PATH

[rhinoceros]

I am now running the command giving the path to the right blastx and see what happens (it is running now). Do you know how i can fix this problem and make sure the blastx runs from the right folder? I assume i should change the PATH? How so?

At the command line:

which blastx

Go ahead and delete the whole dir (except if it's something like /usr/bin or /usr/local/bin in which case just delete the blast binaries). Then change paths in your .bashrc (or equivalent depending on your OS)..

[cdes79]

Thanks all of you for the fantastic help! Everything worked fine!!!

[maubp]

You need BLAST+ 2.2.28 or later for the stitle field and related new columns, see:

http://blastedbio.blogspot.co.uk/2012/05/blast-tabular-missing-descriptions.html