Genetic Distance Calculator (Nei's Distance)

Genetic Distance Calculator

How genetically differentiated are two populations? Nei's standard genetic distance quantifies divergence based on allele frequency differences at a given locus.

Formula

D = -ln(I), where I = Jxy / √(Jx × Jy)
Jx = Σ(freq_A²), Jy = Σ(freq_B²), Jxy = Σ(freq_A × freq_B)

Example

Population A allele frequencies: 0.6, 0.4. Population B: 0.5, 0.5.

Genetic Identity (I) = 0.9806 → Genetic Distance (D) = 0.0196 (very low divergence)

Reading the Distance

A genetic distance of 0 means the two populations have identical allele frequencies at the studied locus; larger values indicate greater divergence, often reflecting longer periods of reproductive isolation, genetic drift, or differing selection pressures between populations. In real population genetics research, this calculation is typically averaged across many loci for a more robust divergence estimate.

Genetic Distance vs. Genetic Relatedness

This measures divergence between entire populations based on allele frequency differences - a distinct concept from genetic relatedness, which measures shared ancestry and similarity between specific individuals (like siblings or cousins) rather than differentiation between whole populations.