The need to test for your Y-Chromosome DNA (Y-DNA) haplogroup depends on your research interests. Taking an extended Y-DNA SNP test such as the Geno 2.0 test is a good idea for those interested in their ancient ancestry and prehistoric migrations. It is also of interest to those interested in historic events. There is potential for haplogroup subbranches to become more useful for genealogical work.

Some Y-DNA subclade markers, SNPs (single nucleotide polymorphisms), are restricted to a single family that is related in genealogical times (1 to 15 generations). These are family SNPs or private SNPs. Other SNPs are slightly older. They represent paternal lineage groups that predate the adoption of a family surname. These are semi-private SNPs. Both private and semi-private SNPs are uncommon.