Question

The gene for brown eyes is dominant over the gene for blue eyes. Identify the correct statements from the following.

• A. Both brown-eyed parents can have blue-eyed child.
• B. Both blue-eyed parents will have a blue-eyed child.
• C. Blue-eyed person will always have both their alleles different from a brown-eyed person.
• D. For a child to be brown-eyed, atleast one parent should be brown-eyed.

Answer 1

Answer: (A), (B), (D)

The correct options are
A Both brown-eyed parents can have blue-eyed child.
B Both blue-eyed parents will have a blue-eyed child.
D For a child to be brown-eyed, atleast one parent should be brown-eyed.


$\bullet$ Genotype for blue-eyes: bb.
$\bullet$ Genotype for brown-eyes: BB or Bb.
$\bullet$ There is probability of having blue-eyed child, only when the parents are brown-eyed with heterozygous condition.
$\bullet$ As blue-eyed is a recessive condition, if the parents are blue-eyed (bb), their child will be always blue-eyed.
$\bullet$ Parent with either BB or Bb genotypes can have children with brown eyes even if the other parent's genotype is bb.
$\bullet$ Alleles in a blue eyed person will be completely different from brown eyed person, only if the genotype of latter is homozygous. Heterozygous brown eyed person (Bb) and a blue eyed person (bb) shows similarity in one allele (b).