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Practice retrieving data and running stand alone BLAST. Step 1. Identify genes in the ABA biosynthesis pathway from the Arabidopsis Cyc database http://www.arabidopsis.org/biocyc/index.jsp Step 2. Identify subject database Vitis vinifera (nucleotide) Solanum pennellii (EST)
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Query: Select Pathway by name Enter: Abscisic Acid Submit
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Now what?
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Filter for unique sequences (EXCEL: Data, Filter, Advanced Filter…)
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Notepad ++ EDIT, LINE OPPERATIONS, JOIN LINES SEARCH, REPLACE, “space” with “spaceORsapce” Paste into ENTREZ Nucleotide search…
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PERL chomp; next if /^\s/; #(skip if there is a space in start of the line) next if /^Gene/; #(if line starts with “gene”, skip) my @temp = split /\t/; #(data set is tab delimited) $hash{$temp[0]} = 1; #(unique sequence i.d. #0 is first element of the array) Then invoke BioPerl to query NCBI with the search string: TAIR:AT### AND “complete cds” Where AT### are the unique accession numbers from AraCyc and “complete cds” eliminates genomic sequence (e.g. complete Ath chrom 4) See complete script on class site….
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Do we want this much sequence?
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Use the push pin to highlight all boxes for mRNA (22 sequences) so we don’t get chromosome 4 genomic sequences
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Try: Use Unix to verify that the file contains all the sequences… Q: What command would you use? A: $ grep –c “>” filename
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(lycopersicum [ORGN] AND EST) AND "Solanum pennellii"[porgn:__txid28526]
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Try: Use Unix to verify that the file contains all the sequences…
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Vitis [ORGN] AND EST Nucleotide
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Note syntax of ENTREZ search invoked by organism tree link
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For class, I recommend downloading the smaller Nucleotide data set…
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Try: Use Unix to verify that the file contains all the sequences…
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Now what? Which file needs to be formatted for BLAST (formatdb)? Which file will be the query file? What is the syntax for the BLAST (including PATH)?
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Formatdb $ /path/formatdb -i /path/filename –p F Run nucleotide BLAST (blastn) $ /path/blastall -p blastn -d /path/filename -i /path/filename –o filename –e 0.01
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