Question

In a population of lizards, being spotted or non-spotted is controlled by a single gene, SS and Ss forms are spotted and ss form is non-spotted. In this population, we found that 58 out of 200 are non-spotted and 142 are spotted. a)Find the frequency of allele S and s? b) Use this allele frequency to find the expected genotypic frequency in this population.c) Calculate the chi-square for the observed and expected values for this population.

Answer 1

a)Find the frequency of allele S and s?

ss form is non-spotted= q^2= 58/200 =0.29

q=0.539

p+q=1

p=1-q

p=1-0.539 =0.461

b) Use this allele frequency to find the expected genotypic frequency in this population.

p^2+2pq+q^2=1

SS=p^2=0.21=21%

ss=q^2=0.29=29%

Ss=2pq=2 x 0.461x 0.539 =0.49 = 49%

c) Calculate the chi-square for the observed and expected values for this population.