Please explain how you got the answer because I really want to understand this.
ID: 207509 • Letter: P
Question
Please explain how you got the answer because I really want to understand this. The professor said that for D the answer is 4/9 and for F the answer is 3/64. Thank you.
Trait Genotype Phenotypic Effect Relationship No disease Human Tay-Sachs Disease T>t Tay-Sachs Disease MG-7. Tay-Sachs disease is a serious neurodegenerative disorder occurring in individuals homozygous for a recessive allele, t a. Mr. and Mrs. D are both unaffected by Tay-Sachs disease and have both a daughter with symptoms of this disease and a normal son (Son D). What is the probability that Son D is a carrier of the recessive allele' b. Ms. E is unaffected by Tay-Sachs disease but has a brother with the disease. If Son D marries Ms. E, what is the probability that their first offspring will be affected by Tay-Sachs disease? c. If Son D and Ms. E have four children, what is the probability that two would be affected by Tay-Sachs disease and two would be unaffected? d. If the first offspring of Son D and Ms. E is an unaffected female, what is the probability that the second child of this marriage would be an unaffected male? e. If the first child born to Son D and Ms. E is affected by Tay-Sachs disease, what is the probability that their second child would be affected by Tay-Sachs disease? If the first child born to Son D and Ms. E is an affected female, what is the probability that the second child will be an affected male and f. that the third child will be an unaffected male?Explanation / Answer
Son D and Ms.E both have genotype Tt. So the genotypes of their offspring can be TT,Tt,Tt,tt.
Probability of being an unaffected individual is 3/4 and being an affected individual is 1/4
Probability of being a boy is 1/2 and being a girl is 1/2
d) So the probability of their second child for being an unaffected male is 3/4*1/2=3/8
f) Probability that the second child will be an affected male and the third child will be an unaffected male is=(1/4*1/2)*(3/4*1/2)=3/64