- EITHER a binary polymorphism (BP) that has been observed only once, or has been observed multiple times but the associated STR profiles show less than 15% of markers have diverged,
- OR a BP for which NO specified population have been demonstrated to exist where the frequency is greater than 0.05% (P<0.05) and whose total male population exceeds 500,000 individuals as defined geographically or ethnically.
In other words, a private SNP occurs at such a low level that it should not be used to define a haplogroup. The term "family SNP" has also been used to refer to private SNPS.
Note: The ISOGG defines a binary polymorphism (BP) as a polymorphism with two states. It could be a single nucleotide polymorphism (SNP) or an insertion/deletion (indel).