Question

On the planet Trogus, the population of Trogites have an autosomal gene, HDZ, with two alleles, T and t. T is dominant to t. Individuals with the T allele in their genotype show a propensity for sorbet, while the remainder prefer ice cream. In multiple population studies, 60% of individuals with the TT genotype prefer sorbet, 25% of Tt individuals prefer sorbet, and 5% of tt individuals prefer sorbet.

In an F1 cross of Tt x Tt genotyped individuals, among the F2 population of individuals who prefer ice cream, what is the probability that a random individual has the TT genotype?

A. 0.333.

B. 0.995.

C. 0.667.

D. 0.001

E. 0.140.

Answer 1

option E is correct 0.140

explanation

Parental cross: Tt X Tt

Progeny: TT Tt Tt tt

Assume that total population size = 100

So,

TT = 25; 40% 0f TT individuals prefer ice cream = 10 individuals

Tt = 50; 75% 0f Tt individuals prefer ice cream = 37.5 individuals

tt = 25; 95% 0f tt individuals prefer ice cream = 23.75 individuals

Total individuals that prefer sorbet = 10 + 37.5 + 23.75 = 71.25

Now, we need to calculate the probability that a random individual is TT

71.25 -----> 100

10 -----> X

X = 10 X 100/71.25

= 14.03%

= 0.140