If the number of people with each phenotype of a two allele system is known, then the gene frequency for each of the two alleles can be calculated.
|
|
Individual
|
X Genes
|
X[a]
|
X[b]
|
|
X(a+b-)
|
c
|
2 * c
|
2 * c
|
0
|
|
X(a+b+)
|
d
|
2 * d
|
d
|
d
|
|
X(a-b+)
|
e
|
2 * e
|
0
|
2 * e
|
|
|
|
|
|
|
|
Totals
|
c+d+e
|
2 * (c+d+e)
|
(2 * c) + d
|
d + (2 * e)
|
frequency of allele X[a] =
= ((2 * c) + d) / (2 * (c+d+e))
frequency of allele X[b] =
= (d + (2 * e)) / (2 * (c+d+e))
