Allele-Frequency Dynamics: Selection, Dominance & Drift |…

What Are Allele-Frequency Dynamics?

Allele-frequency dynamics refer to how the frequencies of different alleles (variants of genes) in a population change over time. These changes are driven by evolutionary forces such as natural selection, genetic drift, and gene flow.

In this 2D simulation, you can observe these dynamics through discrete generations, where each step represents one reproductive cycle for the population.

Key Forces: Selection, Dominance & Drift

Selection is a process by which certain alleles become more or less common in a population based on their fitness. Fitness refers to an allele's ability to contribute to the survival and reproduction of its carriers.

Dominance describes how one allele masks the expression of another when they are both present in the same individual, influencing the observable traits (phenotypes) of the population.

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Genetic Drift

Genetic drift is a random change in allele frequencies that occurs due to chance events. In small populations, genetic drift can have a significant impact on allele frequency over time.

The Wright-Fisher model used in this simulation captures the essence of genetic drift by randomly sampling alleles from one generation to the next.

Real-World Applications

Understanding allele-frequency dynamics is crucial for fields like medical genetics, where it helps predict the spread of diseases and the effectiveness of treatments.

In conservation biology, these principles are used to manage endangered species by predicting how genetic diversity will change under different management strategies.

Frequently asked questions

What is the significance of the selection coefficient in this simulation?

The selection coefficient quantifies the relative fitness advantage or disadvantage of one allele over another. It directly influences how quickly alleles will change frequency within a population.

How does dominance affect the outcome of natural selection?

Dominance can alter the apparent fitness of an allele by affecting its expression in heterozygous individuals, which can lead to different outcomes for natural selection compared to when alleles are completely recessive or dominant.

What is genetic drift and why does it matter?

Genetic drift refers to random changes in allele frequencies that occur due to chance. It matters because in small populations, these random fluctuations can lead to significant changes in the genetic makeup of a population over time.

How do discrete generations affect the dynamics observed in this simulation?

Discrete generations allow for clear observation of how allele frequencies change from one generation to the next. This stepwise approach helps in understanding the long-term trends and fluctuations in genetic diversity within a population.

Try it live

Everything above runs in your browser — open Allele-Frequency Dynamics: Selection, Dominance & Drift (2D) and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Allele-Frequency Dynamics: Selection, Dominance & Drift (2D) simulation