Question about `Allele_count_hom_` variables' meaning

[ramiromagno]

Hello BX Team,

I have a question about the Allele_count_hom_ variables. Their description reads, e.g.:

Count of observed alternate alleles (variant) in exomes of homozygous African/African American Populations, per gnomAD (gnomAD 2.1)

what do you mean by homozygous populations? I understand the adjective applied to individuals, but to populations...? I'm confused.

Initially, I thought these variables would capture the number of alternate alleles in homozygous individuals for the variant of interest. However, that would imply that the values for these variables would always be even (multiple of the two autosomal chromosomes), which is not the case.

Did you mean perhaps:

Count of observed alternate alleles (variant) in exomes of homozygotes in African/African American Populations?

But then again, you are already more explicit in these other variables for the ExAC project, e.g. Homozygous_count_AFR_ExAC, whose description is explicit about this point, stating:

Number of homozygotes with the variant in African populations

so if that was the case you'd had done like for the ExAC, I guess...