Question

3. In fruit flies, two genes S and T have similar function. If either, or both...

3. In fruit flies, two genes S and T have similar function. If either, or both of the genes have at least one dominant allele present, the flies have normal wings. If not, then the wings are small. Two SsTt flies are crossed together. Assuming that the two genes assort independently, what are the expected phenotypes, and their ratios, in their offspring?

8. A male carries a recessive mutation on the X chromosome that causes hemophilia, a blood clotting disorder. He marries a female who is phenotypically normal, but whose father had hemophilia. Suppose they have a child. What is the probability that the child will have hemophilia?

Homework Answers

Answer #1

8. It is a sex linked recessive diseases . In this case , female will be a carrier . She had a gene on one of X chromosome and so could pass it on her children.

If boy carries Y from father and X haemophilic from mother he will be haemophilic and nother X then it will have normal blood clotting .

If girl get X from father and X haemophilic from motjer shw will be haemophilic . And if normal from mother it will be a carrier .

For each four cases they have 25% chances . i

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