Fitness Model for Gene Frequency in Populations

generations

10

20

50

100

fitness of AA

1.

fitness of Aa

0.93

fitness of aa

0.97

p

0

generation k	p k
0	0.450
10	0.478
20	0.516
30	0.565
40	0.628
50	0.703
60	0.785
70	0.860
80	0.918
90	0.956
100	0.977

Imagine a single gene with two alleles, A and a, where the frequency of the A allele in the gene pool of an entire population is

p

0

. Assuming that this is a large and isolated population, that there is random mating, and that there are fixed fitness coefficients for each of the three possible genotypes AA, Aa, and aa through the generations, one can predict the frequency

p

k

of the A allele in the population after

k

generations.

This Demonstration allows you to adjust the values of the fitness coefficients (drag their sliders to the right to improve the fitness of a genotype), and to adjust the initial frequency of the A allele in the gene pool (vertical slider). You may also control how many generations are viewed.