You are studying a population of sparrows in which phenotype is determined by a single locus. Only two alleles for that locus are known for this population which are distinguished by the codes 'A' and 'a'. Distribution of phenotypes in the population indicates that 49% of the population is 'AA' homozygous, 42% are heterozygous, and 9% 'aa' homozygous. How do you determine the allele frequency for 'A' and 'a' based on these observations?

allelic frequency a = 30%

allelic frequency A = 70%

Explanation:

You are studying a population of sparrows in which the phenotype is determined by a single locus. Only two alleles for this locus are known for this population, which are distinguished by the codes 'A' and 'a'. The distribution of phenotypes in the population indicates that 49% of the population is homozygous 'AA', 42% is heterozygous and 9% 'aa' homozygous. How is the allele frequency for 'A' and 'a' determined based on these observations?

According to the case, the allelic frequency for A and a will be searched with the dа ta:

homozygotes AA = 49%

heterozygotes Aa = 42%

homozygous aa = 9%

Frequency of homozygotes 'aa'

(q 2) = 9/100 = 0.09

we can obtain the allelic frequency of a through the following formula:

a (q) = √0.09

The result will be

= 0.3

we change to percentage

= 30%

we have the following formula

p + q = 1

to find the allele frequency A, represented by p

p = 1 - 0.3

we get the following result

p = 0.7

we change to percentage

= 70%