SNAPPY is a software program used to assign Y-chromosome phylogeny-informed haplogroups using dense genotype data. The program efficiently tests all haplogroups from a provided Y-chromosome haplogroup database to find the one that is best supported by input genotypes. Importantly, the method considers both the amount of support for the specific haplogroup, as well as its ancestral haplogroups. This accounts for the underlying genealogy the haplogroups represent, strengthening the accuracy of the assignments.
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