Genetic Distance Calculator
Calculate FST and Nei's genetic distance between populations from allele frequencies. Measure population differentiation and gene flow from single or multi-locus data.
🧬 Population Genetics📐 FST = (HT - HS) / HT🧬 Biology
Allele frequency in population 1
Allele frequency in population 2
Please enter valid values.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Genetic Distance Calculator | — | FST = (HT - HS) / HT | dimensionless 0-1 |
Step-by-Step Examples
Example 1
Human Continental Populations
SNP: freq 0.60 in Europeans, 0.30 in East Asians.
- HT=0.495, HS=0.225
- FST = 0.545 for this SNP
- Average human genome FST ~ 0.10-0.15
✓ FST=0.55 (single SNP, high)
Example 2
No Differentiation
Same frequency p1=p2=0.5.
- HT=0.5, HS=0.5
- FST=0 — identical populations
- No genetic distance
✓ FST=0 — no differentiation
Example 3
Island Population
p1=0.80 (mainland), p2=0.20 (island).
- FST=0.48 — high isolation
- Nei D=-ln(0.52)=0.654
- Large genetic distance from founder effect/drift
✓ FST=0.48 — highly isolated
Real-World Applications
Conservation Genetics
Identify isolated populations for separate management.
Phylogeography
Reveal historical barriers to gene flow.
Population Stratification
Correct for structure in GWAS studies.
Disease Mapping
Quantify population structure in association studies.
Common Mistakes to Avoid
⚠️
Single locus FST is noisy
Genome-wide average from thousands of loci needed for reliable estimates.
⚠️
FST depends on within-population diversity
High heterozygosity markers give lower maximum FST. Use G'ST for comparison.
⚠️
FST ≠ gene flow directly
Wright's Nm formula assumes island model; real migration patterns are complex.
Frequently Asked Questions
What is FST? ▾
Fraction of total genetic diversity between populations. FST=0: identical. FST=1: completely different.
What is global human FST? ▾
~0.10-0.15 between continental groups. ~85-90% of variation is within human populations.
What is Nei's D? ▾
D=-ln(identity coefficient). Ranges 0 (identical) to infinity (no shared alleles).
What does FST=0.05 mean practically? ▾
~5% of variation between groups, 95% within. Corresponds to ~5 migrants/generation by Wright's formula.
What are alternatives to FST? ▾
Jost's D, G'ST, Psi (diploid). Better for high-diversity markers where FST maximum < 1.