Question

A man suffering from recessive X-linked disease marries a normal woman. In the progeny ________________.
A. All sons are diseased
B. All daughter's are diseased
C. All sons are normal
D. None of the above

Answer 1

Hint:-Both matching genes must be defective in recessive inheritance to cause disease. The disorder does not occur or is mild if only one gene in the pair is abnormal. A carrier is considered anyone who has one abnormal gene (but no symptoms). Carriers may transfer to their children abnormal genes.

Complete answer:
Sex-linked disorders are transmitted by one of the X or Y chromosomes by families. X and Y are chromosomes for sex. Dominant inheritance happens when one parent 's abnormal gene causes illness, even though the other parent's corresponding gene is normal. Dominating the abnormal gene. Most commonly, the term "sex-linked recessive" refers to recessive X-linked. X-linked disease manifests usually only in males. A male with an infected allele is hemizygous on his single X chromosome and will not transfer the disease to his male offspring, although it would be mandatory for all his daughters to inherit it. The disease is transmitted to affected sons by stable heterozygous carrier females. So it can be transmitted to male grandchildren via carrier daughter ('diagonal' or 'Knight's step' transmission) from affected males.

Haemophilic man (XhY) fertilises with Normal women (XX) creates following results:

	X	X
Xh	XhX (Carrier)	XhX (Carrier)
Y	XY (Normal)	XY (Normal)

Hence, Option C is the right answer.

Additional Information:
X-linked recessive inheritance: The chance of passing on an X-linked recessive condition also varies between men and women because of the disparity in sex chromosomes. It will not affect the sons of a man with an X-linked recessive condition and one copy of the mutated gene will be borne by his daughters. A woman carrying an X-linked recessive condition has a 50 percent risk of having sons who are affected and a 50 percent chance of having daughters carrying one copy of the mutated gene for each birth.

Note:- In a family, when a genetic disorder is diagnosed, family members also want to know the possibility that the disease will grow for them or their children. In certain cases, this can be difficult to predict since several variables affect the likelihood of an individual having a genetic disorder. How the disorder is inherited is one significant factor.