Question

Bob and Cindy want to have kids. Bob has sickle-cell anemia, which is an autosomal recessive disorder, and his wife Cindy is a carrier. a) If Cindy is pregnant with fraternal (nonidentical) twins, what is the probability that she will have a boy and a girl with sickle-cell anemia? I to be a boy 1/2 to be a girl 1/2 to be normal 1/2 to have sickle-cell UAB log al bled broad indivtilidadoqadi (b anemia b) If the twins are identical how would this change your answer to a)? eraldo netron o novo nobi () mohouwb) bagoloan ob to bude u bilo nimalobong grape victobnoqbal na novo ollu owl.) onda bilioni di un bon bond-Anomwolus ins) bolo bom c) If Cindy and Bob have three children (not twins), what is the probability that none of them will have sickle cell anemia? o svilubong you banon booge u ovo bine lomon odliwo svi oni to to Jedi vilidadorqodi od 18 d) If they have three children, what is the probability that at least one child will have the disease?

Answer 1

The probability of Cindy and Bob having fraternal twins, a boy and a girl both with sickle cell anemia, is 1/64. For identical twins, they would either both have the disease or neither would. For three children, the probability that none have sickle cell anemia is 27/64, while the probability of at least one child having the disease is 37/64.

Step-by-step explanation:

Sickle cell anemia is an autosomal recessive disorder, meaning two copies of the mutated gene are needed for a person to exhibit symptoms of the disease. If Bob has sickle cell anemia and Cindy is a carrier, their potential offspring could have the following genotypic probabilities: 25% SS (unaffected), 50% Ss (carrier), and 25% ss (affected by sickle cell anemia).

a) Probability for Fraternal Twins

To find the probability of having a boy and a girl both with sickle cell anemia, we calculate the following: the chance of having a boy (1/2) multiplied by the chance of having a girl (1/2) multiplied by the chance of each having sickle cell anemia (1/4). This results in 1/2 * 1/2 * 1/4 * 1/4 = 1/64.

b) Probability for Identical Twins

In the case of identical twins, if one twin has sickle cell anemia, the other will also have it as they are genetically identical. Similarly, their sex would be the same, either both boys or both girls.

c) Probability of Three Children without the Disease

The chance that three children would all be unaffected is (3/4)^3, as each child has a 3/4 chance of not having sickle cell anemia. So, the probability is 27/64.

d) Probability of at Least One Child with the Disease

The probability of at least one child having sickle cell anemia can be calculated by subtracting the probability of none having the disease from one (1 - (3/4)^3), which gives 37/64.