Help needed ASAP, Please Agapanthus is a dominant, homozygous leth al trait amon
ID: 65493 • Letter: H
Question
Help needed ASAP, Please
Agapanthus is a dominant, homozygous lethal trait among Telorites from the planet Teleflora. Subjects with this condition love to send flowers. From a group of Telorites heterozygous at the Agapanthus locus (with two alleles: A = dominant (trait) allele, a = recessive (wild-type) allele), 88% of the Telorites have the Agapanthus phenotype, and 12% look wild-type.
Also, true-breeding wild-type Telorites (aa genotype) have 0% penetrance.
A Telorite with the Agapanthus phenotype mates with a true-breeding Telorite with the wild-type phenotype. One of the F1 children is randomly selected and is mated back to the true-breeding wild-type parent. Out of twenty F2 individuals, we observe the following counts:
Eight F2 individuals have the Agapanthus phenotype;
Twelve F2 individuals have the Wild-type phenotype.
The genotype of the randomly-selected F1 subject must be:
A. AA.
B. Aa.
C. Aa or aa.
D. We cannot say with certainty. We need to perform a Chi-square goodness of fit test.
E. aa.
A. AA.
B. Aa.
C. Aa or aa.
D. We cannot say with certainty. We need to perform a Chi-square goodness of fit test.
E. aa.
Explanation / Answer
The possibility of AA genotype is impossible because it is lethal in homozygous state
B.) Aa
Aa X aa
Aa (50% or 0.50) ; aa (50% or 0.50)
Progeny
Frequency
Penetrance of A
A phenotype
a phenotype
Aa
0.50
0.88
0.88 x 0.50 = 0.44 = 4.0 / 100
0.50 – 0.44 = 0.06
aa
0.50
0.0
0.50
total
8 / 20
0.56 = 0.60 / 100 = 12 / 20
Progeny
Frequency
Penetrance of A
A phenotype
a phenotype
Aa
0.50
0.88
0.88 x 0.50 = 0.44 = 4.0 / 100
0.50 – 0.44 = 0.06
aa
0.50
0.0
0.50
total
8 / 20
0.56 = 0.60 / 100 = 12 / 20
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