ohn and Sue are expecting a child, but are concerned about a rare autosomal rece
ID: 144398 • Letter: O
Question
ohn and Sue are expecting a child, but are concerned about a rare autosomal recessive disease that is present in both of their families. In the pedigree below, John is represented as individual III-11 and Sue is represented as individual III-12. John's sister, III-10, and Sue's brother III-13 both do not show evidence of the disease, but John's paternal grandmother and Sue's maternal grandfather both had the disease.
Assign the appropriate symbol to each individual in the pedigree.
Could you help me on this. I got the first one right which was 66.7 but the prob between john and sue I keep getting wrong
Question 9 of 10 Map Sapling Learning macmillan learning John and Sue are expecting a child, but are concerned about a rare autosomal recessive disease that is present in both of their families. In the pedigree below, John is represented as individual 11 and Sue is represented as individual ll1-12. John's sister, llI-10, and Sue's brother, lI-13, both do not show evidence of the disease, but John's paternal grandmother and Sue's maternal grandfather both had the disease 9 Assign the appropriate symbol to each individual in the pedigree 6 10 What is the probability that neither John nor Sue is a carrier? What is the probability that John is a carrier? 2 Number Number Tools Previous Give Up & View Solution O Check Answer Next Exit HintExplanation / Answer
homozygous dominant, heterozygous dominant, homozygous recessive
In the case of a recessive disease, the presence of two recessive genes can give rise to the expression of the disease. Since the disease is caused by the autosomal recessive condition, the genes are distributed to the offspring compulsorily unlike in sexual chromosomes where genes on Y chromosome might not get transmitted to a girl child or a gene on one of the X-chromosomes of the mother might not get into a male child.
Now, an autosomal recessive disease condition can result in the probability of recessive genes to be transmitted with 100% probability to the child that carries both the recessive genes. The probability of John being a carrier is given as 66.7 which is (2/3 per cent). Here, 2 is the number of events in which the recessive gene can be transmitted, which are heterozygous dominant and homozygous recessive. And 3 is the possible number of outcomes which are all the three homozygous dominant, heterozygous dominant, homozygous recessive.
Coming to the probability of neither John nor Sue to be carriers means that they can be disease holders. So, in that case, by calculating the number of events divided by a number of possible outcomes would give the result as 1/3.
1 means they can be diseased as they are not the carriers according to the condition. 3 is the number of possible outcomes. So, there is a 33% chance of John and sue to be not the carriers.
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