Читать книгу Population Genetics - Matthew B. Hamilton - Страница 56

Here, p is used to indicate allele frequency. For hypothesis 1, the observed frequency of the bb genotype is given by:

Expanding the second term gives:

The other allele frequencies can be obtained by similar steps. This must be true under Mendel's second law if the two loci are truly independent.

For hypothesis 2, the frequency of the B allele can be obtained from the fact that all the allele frequencies must sum to 1:

Then subtracting pB from each side gives:

Squaring both sides gives:

The left side of which can be expanded to:

And then:

The last expression on the right is identical to the sum of the first and second expected genotype frequencies for hypothesis 2 in Table 2.3. Expressions for the frequency of the A and O alleles can also be obtained in this fashion.