Question

Assume coat color in rabbits is determined by a two-allele locus with alleles C and c, with C dominant to c. C_ individuals are black and cc individuals are albino. The phenotype frequencies in a population satisfying Hardy-Weinberg conditions are:black 0.91 albino 0.09 What are the frequencies of the two alleles?What are the frequencies of the three genotypes?

Answer 1

a) frequencies of the two alleles -
`q=0.3, p=0.7`

b) the frequencies of the three genotypes -

`p^2=0.49\\2pq=0.42\\q^2= 0.09`

Step-by-step explanation:

Given,

Phenotypic frequency of albino is
`0.09`

Being a recessive allele, the phenotypic frequency will exits in species that have homozygous recessive genotype i,e cc

Thus , the genotypic frequency of "cc" is
`0.09`

As per Hardy Weinberg's equation, frequency of homozygous recessive genotype is represented by "
`q^(2)`"

So, the frequency of recessive allele will be "q"

`q=√(q^2) \\q=√(0.09) \\q= 0.3`

Hence, as per equation
`p+q=1`

`p=1-q\\p=1-0.3\\p=0.7`

Frequency of genotype "homozygous dominant CC" will be

`p^(2) \\0.7^2\\0.49`

As per second equation of Weinberg's equillibrium-

`p^(2) +2pq+q^(2) =1\\0.49+2pq+0.09=1\\2pq=0.42`

Hence,

a) frequencies of the two alleles -
`q=0.3, p=0.7`

b) the frequencies of the three genotypes -

`p^2=0.49\\2pq=0.42\\q^2= 0.09`