Question

4. In Lop-eared rabbits, about 1 in 1000 has curly hair rather than straight hair; curly hair being due to a recessive gene. What is the proportion of curly alleles in the population? What are the frequencies of homozygous straight hair and of heterozygous straight hair individuals in this population? Assume that the population is in Hardy-Weinberg equilibrium.  

Answer 1

In Lop-eared rabbits, about 1 in 1000 has curly hair

according to Hardy-Weinberg equilibrium , p+q=1

so we can say that p² =1/1000 =0.001

                               p=0.032

frequency of curly hair =0.032

then q= (1-0.032)=0.968

        q²=0.37

frequency of homozygous straight hair= 0.37

now, to obtain frequency of heterozygous straight hair we need Hardy-Weinberg equilibrium

p²+2pq+q²=1

or, 0.001+2pq+0.37=1

or 0.371+2pq=1

or 2pq=(1-0.371)=0.629

frequency of heterozygous straight hair= 0.629

thus among 1000 pepople

1000 X 0.001= 1 will have curly hair

1000X 0.37= 370 people will have homozygous straight hair

and 1000 X 0.629=629 people will have heterozygous straight hair.