Biology - Principles of Inheritance and Variation Question with Solution | TestHub
Choose the group of correct statements regarding sex-linked inheritance.
A) Y-linked genes are inherited only in males.
B) X-linked genes are inherited only in females.
C) Colourblindness shows criss-cross inheritance.
D) Haemophilia is Y-linked recessive disorder.
E) The frequency of colourblind women is much less than colourblind men.
Options:
Answer:
Solution:
Statement A is correct. Y-linked genes (holandric genes) are present only on the Y chromosome and are inherited exclusively from father to son, thus appearing only in males.
Statement B is incorrect. X-linked genes are present on the X chromosome and are inherited by both males and females, as males have one X chromosome and females have two.
Statement C is correct. Colourblindness is an X-linked recessive trait and exhibits criss-cross inheritance, meaning it is passed from an affected father to his grandson through his carrier daughter.
Statement D is incorrect. Haemophilia is an X-linked recessive disorder, not a Y-linked disorder.
Statement E is correct. Since colourblindness is an X-linked recessive trait, a male needs only one copy of the defective gene to be affected, whereas a female needs two copies. Thus, the frequency of colourblind women is much less than that of colourblind men.
Therefore, statements A, C, and E are correct.
Answer: A, C and E only
