Question

Which of the following genetic diseases show criss-cross pattern of inheritance?

• A. Haemophilia and colour blindness
• B. Haemophilia, colour blindness and hypertrichosis of ear
• C. Albinism and sickle cell anaemia
• D. Klinefelter's syndrome and Turner's syndrome

Answer 1

Answer: (A)

The transmission of a gene from mother to son or father to daughter is referred to as a criss-cross inheritance. For example, X-chromosome linkage. Criss-cross inheritance is characteristic for X-chromosome-linked recessive mutations. The recessive genes follow the pattern of inheritance of the X chromosome. They are expressed in the hemizygous male but only in the homozygous female. Criss-cross inheritance can be observed in humans as well. All the offsprings of a red–green color blind father are expected to be normal but all the male children of a color-blind mother are expected to be affected. Some of the male grandchildren of color-blind grandfathers will be color-blind, although their sons (the fathers of the grandsons) have normal vision. Colour blindness is also an example of a criss-cross pattern. Thus, option A is correct.