gatk-3.8

History

depristo 6a49e8df34 Significant change to the way subsetting by sample works with monomorphic sites. Now keeps the alt allele, even if a record is AC=0 after the subset. Previously, the system dropped the alt allele, which I don't think is the right behavior. If you really want a VCF without monomorphic sites, use the option to drop monomorphic sites after subsetting. See detailed information below. Right now, if you select a multi-sample VCF file down (or one with filters I see) down to a smaller set of samples, and the site isn't polymorphic in that subgroup, then the alt allele is lost. For example, when selecting down NA12878 from the OMNI, I previously received the following VCF: 1 82154 rs4477212 A . . PASS AC=0;AF=0.00;AN=2;CR=100.0;DP=0;GentrainScore=0.7826;HW=1.0 GT:GC 0/0:0.7205 1 534247 SNP1-524110 C . . PASS AC=0;AF=0.00;AN=2;CR=99.93414;DP=0;GentrainScore=0.7423;HW=1.0 GT:GC 0/0:0.6491 1 565286 SNP1-555149 C T . PASS AC=2;AF=1.00;AN=2;CR=98.8266;DP=0;GentrainScore=0.7029;HW=1.0 GT:GC 1/1:0.3471 1 569624 SNP1-559487 T C . PASS AC=2;AF=1.00;AN=2;CR=97.8022;DP=0;GentrainScore=0.8070;HW=1.0 GT:GC 1/1:0.3942 Where the first two records lost the ALT allele, because NA12878 is hom-ref at this site. My change results in a VCF that looks like: 1 82154 rs4477212 A G . PASS AC=0;AF=0.00;AN=2;CR=100.0;DP=0;GentrainScore=0.7826;HW=1.0 GT:GC 0/0:0.7205 1 534247 SNP1-524110 C T . PASS AC=0;AF=0.00;AN=2;CR=99.93414;DP=0;GentrainScore=0.7423;HW=1.0 GT:GC 0/0:0.6491 1 565286 SNP1-555149 C T . PASS AC=2;AF=1.00;AN=2;CR=98.8266;DP=0;GentrainScore=0.7029;HW=1.0 GT:GC 1/1:0.3471 1 569624 SNP1-559487 T C . PASS AC=2;AF=1.00;AN=2;CR=97.8022;DP=0;GentrainScore=0.8070;HW=1.0 GT:GC 1/1:0.3942 The genotype remains unchanged, but the ALT allele is now preserved. I think this is the correct behavior, as reducing samples down shouldn't change the character of the site, only the AC in the subpopulation. This is related to the tricky issue of isPolymorphic() vs. isVariant(). isVariant => is there an ALT allele? isPolymorphic => is some sample non-ref in the samples? In part this is complicated as the semantics of sites-only VCFs, where ALT = . is used to mean not-polymorphic. Unfortunately, I just don't think there's a consistent convention right now, but it might be worth at some point to adopt a single approach to handling this. Wiki docs updated. Does anyone have critical infrastructure that depends on the previous convention? Let me know so we can coordinate the change. There's a new function subContextFromGenotypes() that also takes a Set<Allele> to handle this type of behavior. git-svn-id: file:///humgen/gsa-scr1/gsa-engineering/svn_contents/trunk@5832 348d0f76-0448-11de-a6fe-93d51630548a	2011-05-21 13:59:16 +00:00
..
broadinstitute/sting	Significant change to the way subsetting by sample works with monomorphic sites. Now keeps the alt allele, even if a record is AC=0 after the subset. Previously, the system dropped the alt allele, which I don't think is the right behavior. If you really want a VCF without monomorphic sites, use the option to drop monomorphic sites after subsetting. See detailed information below.	2011-05-21 13:59:16 +00:00

depristo 6a49e8df34 Significant change to the way subsetting by sample works with monomorphic sites. Now keeps the alt allele, even if a record is AC=0 after the subset. Previously, the system dropped the alt allele, which I don't think is the right behavior. If you really want a VCF without monomorphic sites, use the option to drop monomorphic sites after subsetting. See detailed information below.

Right now, if you select a multi-sample VCF file down (or one with filters I see) down to a smaller set of samples, and the site isn't polymorphic in that subgroup, then the alt allele is lost.  For example, when selecting down NA12878 from the OMNI, I previously received the following VCF:

1       82154   rs4477212       A       .       .       PASS    AC=0;AF=0.00;AN=2;CR=100.0;DP=0;GentrainScore=0.7826;HW=1.0     GT:GC   0/0:0.7205
1       534247  SNP1-524110     C       .       .       PASS    AC=0;AF=0.00;AN=2;CR=99.93414;DP=0;GentrainScore=0.7423;HW=1.0  GT:GC   0/0:0.6491
1       565286  SNP1-555149     C       T       .       PASS    AC=2;AF=1.00;AN=2;CR=98.8266;DP=0;GentrainScore=0.7029;HW=1.0   GT:GC   1/1:0.3471
1       569624  SNP1-559487     T       C       .       PASS    AC=2;AF=1.00;AN=2;CR=97.8022;DP=0;GentrainScore=0.8070;HW=1.0   GT:GC   1/1:0.3942

Where the first two records lost the ALT allele, because NA12878 is hom-ref at this site.  My change results in a VCF that looks like:

1       82154   rs4477212       A       G       .       PASS    AC=0;AF=0.00;AN=2;CR=100.0;DP=0;GentrainScore=0.7826;HW=1.0     GT:GC   0/0:0.7205
1       534247  SNP1-524110     C       T       .       PASS    AC=0;AF=0.00;AN=2;CR=99.93414;DP=0;GentrainScore=0.7423;HW=1.0  GT:GC   0/0:0.6491
1       565286  SNP1-555149     C       T       .       PASS    AC=2;AF=1.00;AN=2;CR=98.8266;DP=0;GentrainScore=0.7029;HW=1.0   GT:GC   1/1:0.3471
1       569624  SNP1-559487     T       C       .       PASS    AC=2;AF=1.00;AN=2;CR=97.8022;DP=0;GentrainScore=0.8070;HW=1.0   GT:GC   1/1:0.3942

The genotype remains unchanged, but the ALT allele is now preserved.  I think this is the correct behavior, as reducing samples down shouldn't change the character of the site, only the AC in the subpopulation.  This is related to the tricky issue of isPolymorphic() vs. isVariant().  

isVariant => is there an ALT allele?
isPolymorphic => is some sample non-ref in the samples?

In part this is complicated as the semantics of sites-only VCFs, where ALT = . is used to mean not-polymorphic.  Unfortunately, I just don't think there's a consistent convention right now, but it might be worth at some point to adopt a single approach to handling this.  Wiki docs updated.

Does anyone have critical infrastructure that depends on the previous convention?  Let me know so we can coordinate the change.

There's a new function subContextFromGenotypes() that also takes a Set<Allele> to handle this type of behavior.

git-svn-id: file:///humgen/gsa-scr1/gsa-engineering/svn_contents/trunk@5832 348d0f76-0448-11de-a6fe-93d51630548a

2011-05-21 13:59:16 +00:00

broadinstitute/sting

Significant change to the way subsetting by sample works with monomorphic sites. Now keeps the alt allele, even if a record is AC=0 after the subset. Previously, the system dropped the alt allele, which I don't think is the right behavior. If you really want a VCF without monomorphic sites, use the option to drop monomorphic sites after subsetting. See detailed information below.

2011-05-21 13:59:16 +00:00