HEREDITY
MONOHYBRID CROSS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The parents may both have recessive genes for blue eyes.
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The child was born during the winter
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Eye color in humans is not an inherited trait
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The child was deprived of oxygen during its birth
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Detailed explanation-1: -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-2: -For two parents with brown eyes to have a blue-eyed child, both parents must genetically be Bb. When this happens, there is a 1 in 4 chance that these parents will have a bb child with blue eyes.
Detailed explanation-3: -Likewise, two brown-eyed parents can have a child with blue eyes, although this is also uncommon.
Detailed explanation-4: -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-5: -Brown eyes + blue eyes = 50% chance of blue eyes, but only if the brown-eyed parent carries a blue-eyed gene. If not, the chance is 0% Brown eyes + brown eyes = 25%, but only if both parents carry the blue-eyed gene. If not, the chance is 0%