1. What is Phenotypic Variance?

Definition: Phenotypic variance (V_P) is the total observable variation in a trait among individuals in a population.

Purpose: This calculator helps researchers and geneticists quantify how much of a trait's variation is due to genetic versus environmental factors.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V_P \) — Phenotypic variance (context-specific)
• \( V_A \) — Additive genetic variance (context-specific)
• \( V_E \) — Environmental variance (context-specific)

Explanation: The total phenotypic variance is the sum of the additive genetic variance and the environmental variance components.

3. Importance of Phenotypic Variance Calculation

Details: Understanding phenotypic variance helps in estimating heritability, studying evolutionary processes, and analyzing quantitative traits.

4. Using the Calculator

Tips: Enter the additive genetic variance (V_A) and environmental variance (V_E) values. Both values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is additive genetic variance?
A: V_A represents the portion of genetic variation due to additive effects of alleles that contribute to the phenotype.

Q2: What does environmental variance include?
A: V_E includes all non-genetic factors affecting the trait, such as nutrition, temperature, and other external conditions.

Q3: Can phenotypic variance be zero?
A: Only if both genetic and environmental variances are zero, which is extremely unlikely in real populations.

Q4: How is this different from broad-sense heritability?
A: This calculates total variance, while heritability (H²) would be V_A/V_P.

Q5: What units are used for variance?
A: The units are squared units of the original trait measurement (e.g., cm² for height).