0.4
0.7
0.837611
0.177202
0.4
0.7
0.837611
0.177202
Nei's Genetic Distance calculator measures the genetic divergence between two populations based on allele frequency differences. Developed by Masatoshi Nei in 1972, this metric quantifies how much two populations have diverged genetically and is widely used in population genetics, conservation biology, and evolutionary studies.
This simplified version works with a single locus with two alleles. You enter the frequency of one allele in each population, and the calculator computes both Nei's genetic identity (I) and Nei's genetic distance (D). Higher D values indicate greater genetic differentiation between the populations.
For a locus with alleles A and B with frequencies x₁, x₂ in population 1 and y₁, y₂ in population 2:
Jxy = Σ(xi × yi) = x₁y₁ + x₂y₂ (cross-population identity)
Jx = Σ(xi²) = x₁² + x₂² (within-population identity, Pop 1)
Jy = Σ(yi²) = y₁² + y₂² (within-population identity, Pop 2)
I = Jxy / √(Jx × Jy) (normalized genetic identity)
D = -ln(I) (Nei's genetic distance)
Inputs
Results
With allele A frequencies of 0.6 and 0.3 in the two populations, the genetic identity is 0.866 and Nei's distance is 0.144, indicating moderate differentiation.
Inputs
Results
Nearly identical allele frequencies produce an identity close to 1 and a distance near 0, indicating very little genetic differentiation between the populations.
A distance of 0 means the two populations have identical allele frequencies at the locus examined, so there is no genetic differentiation detectable at that locus. In practice, D is usually greater than 0, with conspecific populations typically showing D less than 0.1 and different species often showing D greater than 1.0.
This simplified version handles one locus with two alleles. For multiple alleles or multiple loci, you would need to compute Jxy, Jx, and Jy by summing over all alleles and averaging across all loci before calculating I and D. The full formula follows the same principle but with larger summations.
Under certain assumptions, Nei's D is approximately proportional to divergence time: D ≈ 2αt, where α is the overall mutation rate and t is the time since divergence. This relationship allows D to be used as a rough molecular clock for population-level divergence, though many factors can cause deviations.
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