Question

Background Information for Question 1:

You are consulting with a family where in some individuals a mutation that leads to deafness (D) and a mutation that predisposes individuals to early heart failure (H) are linked. Normally these two traits sort independently but, in this family there was a reciprocal translocation moving them to the same chromosome (the two chromosomes affected are shown below). Deafness and early heart failure are both inherited in an autosomal dominant fashion (with respect to hearing and normal heart function). However, deafness is normally present at birth and early heart failure occurs on average at 40 years of age. Amongst the siblings in the family you are consulting with, there are three men (brothers) and one woman (sister). All the siblings are deaf. The sister and the two oldest brothers also have early heart failure, while the youngest brother has not shown symptoms of heart failure yet (he is 27 years old). Hd translocation exchanged tip of D-bearing th chromosome a to d D D H tip of H bearing chromosome Translocation heterozygote normal

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Question 1 A)

If a translocation heterozygote mates with someone who is not deaf and has normal heart function, what is the likelihood of an offspring being deaf and suffering from early heart failure? Show all your work. (Assume no crossing over between D and H in a translocation heterozygote.) (2 marks)

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Question 1 B)

The youngest brother (deaf, no evidence of heart failure yet) has children with a woman who is not deaf and has normal heart function but has a different rare dominant disorder Familial Hypercholesterolemia (F; which leads to high blood pressure). The gene involved in Familial Hypercholesterolemia is on a different chromosome than the genes for deafness (D) and early heart failure (H).

Their first daughter is deaf and their second daughter is not deaf.

If the youngest brother is a translocation heterozygote what is the likelihood his deaf daughter also has high blood pressure and will have early heart failure? Assume no crossing over between D and H in a translocation heterozygote. Show your work or explain your answer. (4 marks)

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Please show all your work so I can understand. Thank you.

Answer 1

Answer: - Page 1 * According to data with a family where in some 1A) Genotype for translocation heterozygote you are consulting individuals. be Dd Hh => Person who is not deaf and has normal heart function ddhh Odlh xodhh ; DH oh dH dh dh Ddth Dahh dd hh ddHh dah dh Dd Hh Dd hh ddhh dh Ddth Ddhh dd Hh dh Dd Hh Dahh ddhh ddth dohh there will be four out of 16 offspring with Ddth genotype that will be deaf and heart failure at early stage. Hence, the probability will be the one., 4

are 1: 8) Page 2 =) okay, you have to start by writing down the genotypes of both this youngest brother and his wife. =) It is stated that he is a translocation hetedo29gote, he is a Ddth but we going to write it like this: Youngest brotheo :HO /dnff -) So we correctly indicate the tsanslocation =) Now, for the wife, it is not stated if she is a dominant homozygous or a heterozygous. since the trait is dominant Let us she is hetero so zy gous. > Then her genotype is: wife : hh dd ff - Note that we have to write the alleles for the 3 traits in both of these . assume

a Page 3 Parents. Now the next step is to make a Pannet square from these parents, but first let us write down the gametes from each one: Brother: four different gametes: HD of HO hf, do f and dhf dhf wife; only 2 different gametes: hd F and hdf (the 2000 comes from choosing the chromosome that lost the H allele because it was translocated). Now the square; HD OF HD h f dof hHh Dd ff (deaf, H hh Dd Ff hodd ff hh dd Ef d heart, poessude) (deaf, hent normal, noomall (noomal, normall pressure) pressure) Pressure) h H h Dd ff (deaf, Hhh od ff hodoff (rosmal, hhdd ff (normal, dlheart, normal (deaf, heast normal, noomal, normal) normal) I normal) G u

- Now we can square: That is 4 Page 4 answer the question. We are asked about the probability of the deaf daughter for also having heart failure and high pressure. => we have to count the whole number of deaf in the offspring offspring 2 - Now we have to count the number of deaf that also has heart failure and high pressure : That is 2 > That is 2 out of 4, which is og 0.5. And that is the answer. The deaf daughter has a likehood of 50% of also developing heart failure and high Pressure X Please give me an upvote.