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Grade 12Zoology

A man whose father is a colourblind,
marry a woman, who is a daughter of
colourblind mother. The offspring of this
couple will be
(a) all daughter and sons are colourblind
(b) 50% colourblind and 50% normal son
(c) carrier normal daughter and colourblind sons
(d) colourblind sons and normal daughter
Please explain the solution in detail.

Profile image of Adarsh
11 Years agoGrade 12
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1 Answer

Profile image of Komal
11 Years ago
carrier normal daughter and colourblind sons

Color blindless is an X-linked recessive disorder. Hence, the sex chromosomes (X and Y) are used when doing the punnet square.

-(c) can be used to represent color blindless, because it is the recessive trait.
-(C) can be used to represent the dominant allele for normal vision.

A man who is colorblind can be represented as (Xc Y)
A female with normal vision can be represented as (XC XC)

Hence, your cross is as follows:

(Xc Y) x (XC XC)

Based on this crossing, you can conclude that there is a 0% chance of producing a son who is colorblind. All males will have normal vision (XC Y)

From this crossing, you can also conclude that 100% of the females will be carriers (XC Xc), and thus have normal vision, because the allele for normal vision dominates the recessive allele for color blindness