obsolete variant copy number complement true Decided to implement copy number related classes at the sequence level, rather than the sequence feature level. In a 'normal' diploid genome, the copy number complement for any feature (on a non-Y chromosome) contains two members. A copy number variation occurs when a complement contains more or less than two members - as the result of deletion or duplication event(s). Note that the 'copy number variation' class in GENO is related to but ontologically distinct form the SO 'copy_number_variation' class. The GENO class refers to a *set* of all copies of a sequence in a genome, where the number of members in the set is in conflict with the genome's normal ploidy (e.g. not two for a diploid genome). The SO class, which is defined as a sequence feature level concept and therefore represents a single continuous extent of sequence, refers to a single copy of duplicated (or deleted) sequence that comprises the set defined by the GENO CNV class. A copy number complement' that has an abnormal number of members (e.g. more or less than two for an autosomal sequence in a diploid genome, as a result of deletion or duplication event(s). copy number variation