Question

A congenital cataract is a clouding of the lens of the eye that is present from birth. The mode of

inheritance for one type of congenital cataract is from a dominant allele. Suppose a man is
heterozygous for this type of congenital cataract, and a woman does not have cataracts. If these two
individuals have a child, what is the probability that the child will have this type of congenital cataract?
a. 25%
b. 50%
c. 75%
d. 100%

Answer 1

The child of a heterozygous man for congenital cataracts and a woman without cataracts has a 50% chance of inheriting the condition. This is due to the dominant nature of the gene causing congenital cataracts, with two possible genetic combinations for the offspring.

Step-by-step explanation:

If a man is heterozygous for congenital cataracts (meaning he has one dominant allele and one recessive allele) and a woman does not have cataracts (and therefore has two recessive alleles), their child would have a 50% chance of inheriting congenital cataracts. The genetic pairing possibilities for this couple are one dominant allele from the father and one recessive allele from the mother (which results in a child with cataracts), or one recessive allele from both parents (resulting in a child without cataracts). Since there are two possibilities and only one results in cataracts, the probability is 1 in 2, or 50%.

Congenital cataracts, often causing significant visual impairment, are a condition where the lens of the eye is cloudy from birth. Adequate light can't enter the eye in this state, leading to difficulty in seeing clearly. Vitamins such as A and C may help prevent the formation of cataracts by protecting ocular health.