Minimum Allele Frequency (Minimum Frequency Ceiling)
Definition
A conservative lower bound applied when an allele is absent or very rare in the database, to prevent an artificially inflated match probability statistic. Common values are 5/2N (where N is the database size) or a fixed floor such as 0.001 (one in a thousand).
Related terms
- Allele Frequency
- The proportion of a specific allele variant at a given genetic locus in a defined population. Forensic match probability calculations multiply the...
- Hardy-Weinberg Equilibrium (HWE)
- The expected genotype frequency in a large, randomly mating population with no selection, mutation, or migration. Under HWE, the frequency of a...
- Population Substructure
- The condition in which allele frequencies differ systematically between subgroups within a nominally single population. Substructure means that individuals within a subgroup...
- Reference Population Database
- A curated collection of allele frequencies or feature measurements from a defined population, used to estimate the probability that a randomly chosen...
- Theta Correction (FST or Coancestry Coefficient)
- A statistical adjustment applied to DNA match probability calculations to account for expected allele-sharing within subpopulations due to substructure. A theta value...
Explained in
- Population Databases for Forensic StatisticsA conservative lower bound applied when an allele is absent or very rare in the database, to prevent an artificially inflated match probability statistic. Comm...