Genetic Drift Probability Calculator
Calculate genetic drift probabilities and heterozygosity changes using the Wright-Fisher model for population genetics studies.
Input Parameters
Enter population parameters to calculate genetic drift probabilities.
Effective population size (N_e)
Frequency of allele A (between 0 and 1)
Optional: for heterozygosity calculations
Drift Interpretation
P(fixation) >50%
Allele likely to become fixed in population.
P(fixation) ≈ P(loss)
Moderate drift effects expected.
P(loss) >50%
Allele likely to be lost from population.
Genetic Drift Formula
P(fixation) = p
Probability of fixation equals initial allele frequency. P(loss) = 1 - p.
Wright-Fisher Model
Mathematical model for genetic drift in finite populations.
Effective Population Size
Idealized population size that loses heterozygosity at the same rate.
Genetic Drift Probability Calculator & Wright-Fisher Model Guide
Genetic drift is a fundamental stochastic mechanism of biological evolution involving massive random variations in allele frequencies. Our built-in Genetic Drift Probability Calculator correctly utilizes the proven Wright-Fisher generation model to strictly help biologists, genetic researchers, and educators seamlessly quantify exactly how effective population sizes govern genetic stability, mutation variation, and eventual allele fixation probabilities in distinctly finite populations.
Key Wright-Fisher Genetic Formulas
The Wright-Fisher algorithm predicts drift effects relying predominantly on the initial frequency count against global capacity thresholds.
Fixation Probability: P(fixation) = p₀
Loss Probability: P(loss) = 1 - p₀
Expected Fixation Time: E[T_fix] = -2N[p₀·ln(p₀) + (1-p₀)·ln(1-p₀)]
Variance (Alelle Freq Change): Var(Δp) = p₀(1-p₀)/(2N)
- p₀: The initial biological frequency observed for the specific allele.
- N: The overall effective breeding population capacity (N_e).
Stochastic Principles & Drift Variance
Unlike natural selection (which actively favors superior biological traits adaptively), Genetic Drift purely constitutes random statistical sampling anomalies that rapidly accumulate generationally.
- Population Size Dictates Severity: Because the exact variance of frequency entirely hinges upon
1/(2N), remarkably smaller ecological populations endure significantly stronger drift destabilization. - Heterozygosity Decay: Finite genetic reserves perpetually lose heterozygosity variants at a predictable structural rate of
1/(2N)strictly per generation cycle, pushing isolated cohorts inherently towards pure genetic homozygosity. - Adaptive Danger: Critical instances of acute drift perfectly mirror severe population "bottlenecks", dramatically accelerating vulnerability and increasing absolute extinction peril exactly by eroding critical protective adaptations.
Academic & Scientific References
For further understanding and validation of the formulas used above, we recommend exploring these authoritative resources: