A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy

must have normal colour vision

will be partially colourblind since he is heterozygous for the colourblind mutant allele

must be colourblind

may be colourblind or may be of normal vision

Solution

may be colourblind or may be of normal vision

Colourblindness is a sex linked disorder (X- linked). It is always transferred from mother to son.

In the mentioned question, woman whose father was colourblind, will be the carrier of the colourblind trait. If this woman marries a colourblind man, following possibilities are possible-

(i) If woman is Normal-

(ii) If woman is Carrier-

Hence, in both the cases, boy may be colourblind or may be of normal vision.

Some More Questions From Principles of Inheritance and Variation Chapter

For Daily Free Study Material Join wiredfaculty

Principles Of Inheritance And Variation

Some More Questions From Principles of Inheritance and Variation Chapter

What is Mendel’s monohybrid phenotypic ratio ?

Write down Mendel’s dihybrid Phenotypic ratio

Who were the rediscoverers of Mendelism ?

What are the real determinants of what an organism will become ?

What is the unique feature of F1 generation ?

What will be the genetic make up of an organism which suffers from sickle cell anaemia ?

What do the symbols square and circle in a pedigree chart indicate ?

Define heterogamy. Give an example.

How many chromosomes are found in human cells ?

Why is male Drosophila regarded as heterogametic ?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Location