Heritability Calculator
Calculate narrow-sense h2 and broad-sense H2 heritability from variance components. Find what proportion of phenotypic variation is due to additive genetic effects. Essential for quantitative genetics.
🧬 Genetics📐 h² = VA / VP🧬 Biology
Additive genetic variance VA
Total phenotypic variance VP
Dominance variance VD (optional)
Environmental variance VE (optional)
Please enter valid values.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Heritability Calculator | — | h² = VA / VP | 0 to 1 |
Step-by-Step Examples
Example 1
Human Height
VA=0.45, VP=0.60 (from twin studies).
- h2=VA/VP=0.45/0.60=0.75
- 75% of height variation is additive genetic
- Remaining 25% is environmental and non-additive
✓ h2=0.75 — highly heritable
Example 2
IQ Scores
VA=0.30, VP=0.50.
- h2=0.30/0.50=0.60
- 60% additive genetic
- h2 is population and environment specific
✓ h2=0.60
Example 3
Crop Yield
VA=120, VD=40, VP=240.
- h2=120/240=0.50
- H2=(120+40)/240=0.67
- Narrow h2 predicts selection response
✓ h2=0.50, H2=0.67
Real-World Applications
Plant Breeding
h2 predicts improvement per generation of selection.
Quantitative Genetics
Central parameter for understanding complex trait genetics.
Animal Breeding
Milk yield h2~0.3, growth rate h2~0.4.
Twin Studies
MZ vs DZ twin correlations estimate heritability.
Common Mistakes to Avoid
⚠️
h2 is population and environment specific
Heritability changes with the population and environment studied, not a fixed property of a trait.
⚠️
High h2 does not mean not changeable
Height h2=0.8 but improved nutrition dramatically changed heights in the 20th century.
⚠️
Narrow vs broad heritability
Narrow h2=VA/VP predicts selection response. Broad H2 includes dominance and epistasis.
Frequently Asked Questions
What is heritability? ▾
Proportion of phenotypic variance due to genetic variance. h2=VA/VP. Ranges 0-1. High: mostly genetic variation. Low: mostly environmental.
What is narrow vs broad heritability? ▾
Narrow h2=VA/VP predicts response to selection. Broad H2=(VA+VD+VI)/VP includes all genetic effects.
How is heritability estimated? ▾
Twin studies, parent-offspring regression, half-sib breeding designs, GWAS/GREML with genomic data.
What is the breeder equation? ▾
R=h2 x S. Response to selection = heritability x selection differential. High h2 = faster genetic gain per generation.
Can heritability exceed 1? ▾
No, h2 and H2 are both between 0 and 1. Values above 1 indicate errors in variance component estimation.