diff --git a/TUTORIAL b/TUTORIAL index 92af96b..e192d9e 100644 --- a/TUTORIAL +++ b/TUTORIAL @@ -15,7 +15,7 @@ Bowtie Getting Started Guide genome. To use Bowtie to align those reads, issue the following command. If you get an error message "command not found", try adding a "./" before the "bowtie". - + bowtie e_coli reads/e_coli_1000.fq The first argument to bowtie is the basename of the index for the @@ -26,7 +26,7 @@ Bowtie Getting Started Guide about a minute. You will see bowtie print many lines of output. Each line is an alignment for a read. The name of the aligned read appears in the leftmost column. The final line should say "Reported 698 - alignments to 1 output stream(s)" or something similar. + alignments to 1 output stream(s)" or something similar. Next, issue this command: @@ -82,14 +82,15 @@ Bowtie Getting Started Guide The pre-built E. coli index included with Bowtie is built from the sequence for strain 536, known to cause urinary tract infections. We will create a new index from the sequence of E. coli strain O157:H7, a - strain known to cause food poisoning. Download the sequence file from: + strain known to cause food poisoning. Download and decompress the + sequence file from: - ftp://ftp.ncbi.nlm.nih.gov/genomes/Bacteria/Escherichia_coli_O157H7/NC_002127.fna + ftp://ftp.ncbi.nlm.nih.gov/genomes/refseq/bacteria/Escherichia_coli/all_assembly_versions/GCF_000513035.1_E._coli_O157/GCF_000513035.1_E._coli_O157_genomic.fna.gz - When the sequence file is finished downloading, move it to the Bowtie + Once it has been downloaded and decompressed, move it to the Bowtie install directory and issue this command: - bowtie-build NC_002127.fna e_coli_O157_H7 + bowtie-build GCF_000513035.1_E._coli_O157_genomic.fna e_coli_O157_H7 The command should finish quickly, and print several lines of status messages. When the command has completed, note that the current @@ -100,7 +101,7 @@ Bowtie Getting Started Guide To test that the index is properly installed, issue this command: - bowtie -c e_coli_O157_H7 GCGTGAGCTATGAGAAAGCGCCACGCTTCC + bowtie -c e_coli_O157_H7 GAACCGTATTCACCCGCCATCCCCATGCCG If the index is installed properly, this command should print a single alignment and then exit. @@ -132,16 +133,16 @@ Bowtie Getting Started Guide accessible in the PATH. samtools view -bS -o ec_snp.bam ec_snp.sam - + Next, we sort the BAM file, in preparation for SNP calling: samtools sort ec_snp.bam ec_snp.sorted - + We now have a sorted BAM file called ec_snp.sorted.bam. Sorted BAM is a useful format because the alignments are both compressed, which is convenient for long-term storage, and sorted, which is conveneint for variant discovery. Finally, we call variants from the Sorted BAM: - + samtools pileup -cv -f genomes/NC_008253.fna ec_snp.sorted.bam For this sample data, the 'samtools pileup' command should print