Hi.

I made vcf files using UnifiedGenotyper in GATK and found that many of mutants had 1/2 at genotype (GT) field. 

As I understand, 0/0 = homo ref, 0/1 = hetero, 1/1 = homo alt.

Does anyone know what exactly 1/2 mean?

Thank you!
There are apparently two alternate alleles at this position. So if the reference is `C`, then perhaps you have an `A` and a `G`.