Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

ZoologyPrinciples of Inheritance and VariationGenetic DisordersEasy2 minPYQ_2020
ZoologyEasysingle choice

Mahesh (who is colourblind) and Soni (who is not colourblind) have a daughter Alia. Rishi (who is not colourblind) and Neetu (who is a carrier) have a son Ranbeer. Alia and Ranbeer get married. What is the probability that their daughter will be colourblind?

Options:

Answer:
B
Solution:

The genotype of Alia will be XXc since she receives only one Xc chromosome (colourblindness chromosome) from her father. Ranbeer may be XY or XcY (since his mother is a carrier).

So we consider two possibilities:

1 .  Alia XXc and Ranbeer XY. In this, the daughters could be XX (not colourblind) or XXc (not colourblind)

2 .  Alia XXc and Ranbeer XcY. In this, the daughters could be XXc (not colourblind) or XcXc (colourblind)

Thus there is only 1 in 4 chance that their daughter will be colourblind.

Stream:NTA_ABHYAS_NEETSubject:ZoologyTopic:Principles of Inheritance and VariationSubtopic:Genetic Disorders
⏱ 2mℹ️ Source: PYQ_2020

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