Question

In man brown eyes (B) are dominant over blue eyes (b). A blue-eyed man marries a brown-eyed woman whose mother had blue eyes. What proportion of children are expected to have blue eyes?
(a)100%
(b)75%
(c)50%
(d)25%

Answer 1

Hint: When the cells produce two separate alleles (one wild-type allele and one mutated allele) of a gene, a diploid organism is heterozygous at a gene locus. The phenotypical mixture of both parents would result equally in all the offspring. Half the offspring would be blue-eyed, according to the question, and half the offspring would be brown-eyed.

Complete answer:
The heterozygous female is crossed with a recessive male in this question, so we can decipher from the Punnett square that only 50 percent of all the offspring will have blue eyes.
The genotype Bb must be a brown-eyed man whose mother was blue-eyed, where B represents brown-eye color and b represents blue-eye color. When a man with this genotype is married to a woman with blue eyes, the children are 50 percent blue and 50 percent brown.
A Punnett square is a graphical representation of an offspring's potential genotypes resulting from a specific cross or breeding event. Creating a Punnett square involves comprehension of the parents' genetic makeup. The numerous possible combinations of their gametes in a tabular format are encapsulated. Therefore, each table box represents one event of fertilization.
The inherent assumption is that a single gene locus dictates each trait and that different traits differ independently from each other. While this is true for many useful characteristics, there are many exceptions, especially when choosing characters for plant or animal breeding.
So, the correct answer is, ‘50%’.

Note: Our eyes' color is due to the color of the eye's iris, which is used to block the entrance of excess light into the eye. The dominant eye color is a dark color, such as brown, and the light color, such as blue, is a recessive color. Eye color is actually caused by a set of genes, not just one gene. But, based on a standard Punnett square monohybrid cross, we can draw some pretty accurate assumptions regarding eye color.