Wright–Fisher Neutral Genetic Drift
Keep the expected allele frequency fixed while random reproduction erases genetic diversity.
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Wright–Fisher Neutral Genetic Drift
This module illustrates how haploid populations change allele frequencies over discrete generations purely through random reproduction.
Worked Example
Given 4 gene copies with 2 initially holding the tracked allele, after 5 generations the expected heterozygosity is approximately 0.11865.
- Initial gene copies M = 4, tracked initial copies i0 = 2.
- Generations t = 5.
- Expected frequency remains p0 = 2/4 = 0.5.
- Expected heterozygosity declines as 2p0(1 - p0)(1 - 1/M)t = 2(0.5)(0.5)(1 - 0.25)5 ≈ 0.11865234375.
Experiment
- Adjust the Initial copies to see different starting states.
- Change Generations to observe long-term behavior.
- Observe that fixing the initial frequency causes variance to spread towards 0 and 1, eventually absorbing at the boundaries.
Explore this concept in the interactive module: Wright–Fisher Neutral Genetic Drift.
Limitations
This module assumes no mutation, migration, or selection pressures, tracking purely neutral drift in a finite haploid population.
References
For more details on the derivations and underlying evolutionary theory regarding genetic drift and allele fixation, consult the Cambridge biological lecture notes:
https://people.bss.phy.cam.ac.uk/courses/biolectures/Lecture_Evo_2024.pdf
Experience it interactively
Adjust parameters, observe in real time, and build deep intuition with Riano’s interactive Wright–Fisher Neutral Genetic Drift module.
Try Wright–Fisher Neutral Genetic Drift on Riano →