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Genetic Drift Variance Calculator

Estimate the random change in allele frequency per generation.

Inputs

Results

Std. deviation of change per generation0.05
Heterozygosity lost per generation1%

Chart

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How to use the genetic drift variance calculator

Estimate the random change in allele frequency per generation. Enter allele frequency p, effective population size in the fields above; the std. deviation of change per generation, heterozygosity lost per generation are computed instantly and plotted on the chart so you can see how the answer changes.

Formula

Std. deviation of change per generation = √(p × (1-p) / (2 × N))
Heterozygosity lost per generation (%) = 100 / (2 × N)

Variables

  • p — Allele frequency p
  • N — Effective population size

Worked example

With allele frequency p = 0.5, effective population size = 50, the calculator gives std. deviation of change per generation ≈ 0.05; heterozygosity lost per generation ≈ 1 %.

Frequently asked questions

What is the formula for the genetic drift variance calculation?

Std. deviation of change per generation = √(p × (1-p) / (2 × N)). Heterozygosity lost per generation (%) = 100 / (2 × N). Here p is allele frequency p, N is effective population size.

What inputs do I need for the genetic drift variance calculator?

You need allele frequency p, effective population size. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.

How do I use this calculator?

Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.

Is the result exact?

Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.

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