Question: How to combine chromosome vcf files
gravatar for williamsbrian5064
10 months ago by
williamsbrian5064160 wrote:


Easy question here. I am split up my vcf file up by chromosome to try and save some time. I want to combine the files now to have one complete vcf file with all the chromosomes. Do I wanted to merge the files or do I want to concatenate the files?

I just ran the command

cat *.vcf > cat.chr1.chr2.vcf

This was only on two of the chromosomes and when I went to look at the files, there was only data for the first chromosome and nothing for the second. Am I doing something wrong here? I could also try vcf tools if this "cat" command wont work for what I am trying to do.

ADD COMMENTlink modified 10 months ago by Pierre Lindenbaum119k • written 10 months ago by williamsbrian5064160
gravatar for Pierre Lindenbaum
10 months ago by
France/Nantes/Institut du Thorax - INSERM UMR1087
Pierre Lindenbaum119k wrote:

first alternative, use one vcf file to get the header, and the concatenante all the other vcf without the header (this was your error)

grep '^#' chr1.vcf > merge.vcf
grep -v '^#' chr1.vcf  chr2.vcf chr3.vcf chr4.vcf   >> merge.vcf

second alternative: use picard gatherVcfs, which is going to check the headers, orders etc...

java -jar picard.jar GatherVcfs I=chr1.vcf  I=chr2.vcf I=chr3.vcf I=chr4.vcf  O=merged.vcf
ADD COMMENTlink written 10 months ago by Pierre Lindenbaum119k

Wonderful Pierre! Worked like a charm! Thank you so much for the help!

ADD REPLYlink written 10 months ago by williamsbrian5064160

Hi Pierre, I wanted to merge VCF files which had already splitted by chromosones into a single file. Though each is compressed i.e. chr1.vcf.gz, chr2.vcf.gz, ......chrn.vcf.gz.

I could not see any an output file merged.vcf.gz when I used the command. Is it because the file is compressed?

java -jar /programs/picard-tools-2.18.11/picard.jar GatherVcfs I=chr1.vcf.gz I=chr2.vcf.gz O=merged.vcf.gz
ADD REPLYlink written 11 weeks ago by mab65820
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