OBJECTIVE LIFE SCIENCE
GENETICS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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One person passes on the blue-eye allele.
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They each pass on the blue-eye allele.
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One person’s parents are blue-eyed.
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One person’s grandparents are blue-eyed.
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Detailed explanation-1: -Brown eye colour is dominant over blue eye colour. Therefore, for the brown-eyed parents having blue-eyed child, the possibility is that both have heterozygous genotype i.e. Bb. Therefore, from the square below, it is clear that there is a 25% possibility of blue-eyed (bb) child.
Detailed explanation-2: -The brown eye form of the eye color gene (or allele) is dominant, whereas the blue eye allele is recessive. If both parents have brown eyes yet carry the allele for blue eyes, a quarter of the children will have blue eyes, and three quarters will have brown eyes.
Detailed explanation-3: -Phenotype shown as brown or blue while dominant brown gene = B and recessive blue gene = b Individuals with bb have blue eyes, while individuals with BB or Bb have brown eyes. Blue or brown describes only a portion of eye colour.