Try these parameter values:
Low Allelic Frequency, Smaller Population Size
N: 500
f(a): 0.1
Moderate Allelic Frequency, Smaller Population Size
N: 500
f(a): 0.5
Moderate Allelic Frequency, Larger Population Size
N: 5000
f(a): 0.5
Adjust the initial allelic frequency and population size to the right.
Five selectively neutral genes are present in the population for this simulation. Notice that the initial allelic frequency f(a) determines the proportion of alleles that become fixed as opposed to lost. Also note that as the population size (N) is increased, the effect that genetic drift has on the population size is decreased.
If you continue to press run, without pressing reset, the all alleles will eventually become fixed or extinct. Since there is no mutation in this simulation, the lost alleles cannot be recovered.
The probability of fixation of a selectively neutral allele already present in the population is equal to it's current frequency in the population. The probability of loss, conversely, is equal to 1.0 minus its frequency. This means that if the allelic frequency is 0.5 the allele has an equal chance of becoming fixed as it does being lost.
The average time to extinction or fixation of a selectively neutral allele is inversely related to the population size.
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