Question

A colorblind man marry with a daughter of colourblind father,the generation will be
A. There will be no daughter colourblind
B. All sons will be colourblind
C. All daughter will be colourblind
D. Half of the sons will be colourblind

Answer 1

Hint: Colour blindness is a condition characterised by a reduced ability to distinguish between certain colours especially red and green. It is mostly inherited and other causes of colour blindness include underlying disease. It is a sex-linked trait i.e. the genes for this are present on either X or Y chromosome.

Complete answer:
-The inheritance of x linked trait is known as x linked inheritance. The type of chromosome in human females is xx and in human males it is XY.
-In x linked inheritance it is the males that get affected because they possess only one x chromosome. As a result, there is no extra x chromosome to mask the effect.
-In this question, the daughter of a colourblind father will be a carrier of colour blindness but will not be affected. She will be a heterozygous carrier but will be normal phenotypically. If this daughter is now married to a colourblind man, they will have daughters who will be a carrier in the ratio of 1:1. However, the males that will be born will be half colourblind.

Hence, the correct answer is option (D).

Note: There is no treatment for colour blindness if it is inherited. Colour blindness progression depends on the mutation. The colour blindness can be either static which means there is no progression occurring. Or it can change persistently throughout the age. The two most important forms of colour blindness which are inherited are the protanomaly and deuteranomaly.