Brown eyes are dominant over blue eyes in humans. The genetic makeup of blue-eyed children who have brown-eyed

Brown eyes are dominant over blue eyes in humans. The genetic makeup of blue-eyed children who have brown-eyed parents must be __________________.





A) bB


B) BB


C) Bb


D) bb


E) None of the aboveBrown eyes are dominant over blue eyes in humans. The genetic makeup of blue-eyed children who have brown-eyed
the answer is certainly d)


this is bcoz the child is blue eyed ie recessive


so both the alleles have to be same for its expression


however the parents would be Bb%26amp; BbBrown eyes are dominant over blue eyes in humans. The genetic makeup of blue-eyed children who have brown-eyed
The correct answer is C: Bb. Do a punnett square. If the parents have brown eyes and have a blue eyed child, they must be heterogeneous for the brown eyed trait. That means they don't have BB but Bb (gene for both brown and blue but brown dominates), If you do the square and put B and b over the top left and right squares and a B and b beside the top and bottom left side squares then cross them, you will come out with one BB offspring, 2 Bb offsprings and 1 bb offspring. In other words one homogenous for brown eyes (2 dominant B genes), 2 heterogenous for brown eyes (1 B and 1 b) and one homogenous for blue eyes (bb).
This sounds like a trick questions. Both parents would have to have the recessive blue gene. So theirs would be ';Bb';. But the child's genes would be ';bb'; which is what it is asking. The first part of the question is just a filler to confuse you.
The answer is D) bb





Blue eyes are a recessive trait, therefore both parents have to be heterozygous (Bb).