NEET Biology question

Study the two cases carefully: Case I — mother affected, father normal, sons always affected with the disease. Case II — mother affected, father normal, sons and daughters could both show the disease. What would be the correct interpretation of the two cases?

(A)Case I: X-linked recessive disease; Case II: Autosomal recessive diseaseCorrect
(B)Case I: Y-linked recessive disease; Case II: X-linked recessive disease
(C)Case I and II: X-linked recessive disease
(D)Case I: X-linked dominant disease; Case II: Autosomal dominant disease

Answer: (A)

Solution

In Case I, an affected mother transmits the disease to *all* her sons while the father remains unaffected — this is the classic criss-cross pattern of X-linked recessive inheritance, where a homozygous recessive mother passes her single X (carrying the recessive allele) to every son, who, being hemizygous, is

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Question ID VK-120406