Question

A population of Hawaiian Drosophila is segregating two alleles, S and T, of the PGI gene. In a sample of 100 flies form this population, 30 were SS, 60 were ST and 10 were TT. What is the frequency of the S allele?

Select one:

A. 0.30

B. 0.40

C. 0.50

D. 0.60

E. 0.70

Answer 1

Answer- option D 0.60

Total population = 100

SS= 30

ST = 60

TT=10.

Now ST is Heterozygous and are 60 in number so half will be S and half will be T . So S= 30 and T= 30.

Frequency of S allele in population

= SS + S from ST = 30 + 30 = 60

60/100 = 0.60 .

Now according to hardy weinberg principle

p+q= 1

So 1- p = q

So frequency of q=T= 1-0.6

= 0.4.

To check if the frequencies are correct both should add up to form 1 .

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