[kaps]

I have generated fastq files (R1& R2) from the mapped bam file and I am now interested in assembling those reads using velvet. I need guidance to how to run velveth, velvetg and viewing the output.

[kaps]

Hi Kaps,

you should have a look at the Bowtie2 homepage. There, it is explained in detail how the programs work. At the end of the manual is a "Lambda phage example", which has quite an overlap to your problem. It also has a SAMtools downstream section...

Cheers,
Michael

I have used a reference (comprising of 2 sequences varying in length) to do alignment on paired end fastq files. I have generated the sam file but when i try converting it (sam) to bam, it is not working!
here is the feedback: samtools view -bS 4_S4_paired.sam 4_S4_paired.bam
[main_samview] random alignment retrieval only works for indexed BAM or CRAM files.
▒BC▒m▒▒N▒0D▒ܜK▒X=p[▒qU|
▒ ▒▒▒5r[SY▒I▒▒▒O▒sH[@▒▒▒f▒▒▒a0▒w3▒Rʄq▒▒G▒[▒2▒▒Q▒Lk▒֋▒ vU▒1)J▒ei▒M&"▒qq5▒Q^ݒ▒▒▒▒▒`▒ U▒▒▒Q▒ vI▒▒▒f▒▒q▒▒:;▒=▒▒P▒▒U▒▒"n\o3▒ε▒
▒;*(n▒J)*▒▒▒▒֙%▒zM19H▒I▒▒▒▒▒5{▒>▒S▒H▒Qt▒~▒▒▒
▒▒y▒▒

when with -bT, I get a similar feedback as;
samtools view -bT cp4genome.fa 4_S4_paired.sam 4_S4_paired.bam
[samfaipath] build FASTA index...
[fai_build_core] different line length in sequence '4_S4_contig_23'.
[samfaipath] fail to build FASTA index.
[main_samview] random alignment retrieval only works for indexed BAM or CRAM files.
▒BC▒m▒▒N▒0D▒ܜK▒X=p[▒qU|
▒ ▒▒▒5r[SY▒I▒▒▒O▒sH[@▒▒▒f▒▒▒a0▒w3▒Rʄq▒▒G▒[▒2▒▒Q▒Lk▒֋▒ vU▒1)J▒ei▒M&"▒qq5▒Q^ݒ▒▒▒▒▒`▒ U▒▒▒Q▒ vI▒▒▒f▒▒q▒▒:;▒=▒▒P▒▒U▒▒"n\o3▒ε▒
▒;*(n▒J)*▒▒▒▒֙%▒zM19H▒I▒▒▒▒▒5{▒>▒S▒H▒Qt▒~▒▒▒
where is the problem?

[Michael.Ante]

Hi Kaps,

try

samtools view -S 4_S4_paired.sam | head

if you don't get any problems there, proceed with

 samtools view -bSh 4_S4_paired.sam > 4_S4_paired.bam

The missing '>' was then the problem. If the sam file doesn't have any header lines, you'll need to provide these additionally.

Cheers,

Michael

[kaps]

its working.

Thanks