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1. What are the probabilities of blood genotypes and phenotypes for the offsprin

ID: 92067 • Letter: 1

Question

1. What are the probabilities of blood genotypes and phenotypes for the offspring from a cross between a mother with IAIA blood and a father with IBi blood?

2. Hemophiliacs have blood that does not coagulate well, and they often die at a young age. The disease allele is recessive and X-linked. The normal allele (N) is completely dominant over the disease allele (n). If a hemophiliac woman and a non-hemophiliac (normal) man have children, what percentage of their sons would be expected to have the disease? What percentage of their daughters would be expected to have the disease?

3. If a woman who is heterozygous for the hemophilia trait and a hemophiliac man have children, what percentage of their sons would be expected to have the disease? What percentage of their daughters would be expected to have the disease?

Explanation / Answer

Answer:

Answer:

1).

IAIA X IBi-------Parents

IB

i

IA

IAIB (AB, ½)

IAi (A, 1/2)

The phontypic and genotypic probabilities of progeny is same and is as follows.

Blood group, AB progeny = ½

Blood group, A progeny = ½

2).

hemophiliac woman (XnXn) x   non-hemophiliac (normal) man (XNY)----Parents

XN

Y

Xn

XNXn (normal daughter, 1/2)

XnY (hemophiliac son, 1/2)

All daughters are normal and all sons are hemophiliac.

The percentage of their sons would be expected to have the disease= 100%

The percentage of their daughters would be expected to have the disease= 100%

3).

Heterozygous woman (XNXn) x hemophiliac man (XnY)-----Parents

Xn

Y

XN

XNXn (normal daughter)

XNY (normal son)

Xn

XnXn(hemophiliac daughter)

XnY (hemophiliac son)

The percentage of their sons would be expected to have the disease= 50%

The percentage of their daughters would be expected to have the disease= 50%

IB

i

IA

IAIB (AB, ½)

IAi (A, 1/2)