bcftools concatenation error

Question

[GK1610]

I have 22 vcf files from each chromosomes. I am try ing to concatenate the vcf files

bcftools concat -f files.txt -Oz > merged.vcf

I keep getting this error:

chromosome 9 is not contiguous, consider running with -a.

How can I resolve this issue?

Answer 1

[swbarnes2]

Well....why can't you run it with -a?