Which Child Best Exemplifies the Homozygous Inheritance of a Recessive

Question

Which child best exemplifies the homozygous inheritance of a recessive genetic disease:
A) a child who will have cystic fibrosis
B) a child with two dominant alleles for the disease
C) a child who will NOT get cystic fibrosis.
D) a child who will be a heterozygous carrier for cystic fibrosis
E) a child with a balanced polymorphism.

Accepted Answer

Homozygous inheritance of a recessive genetic disease means that the individual has two copies of the recessive allele, which is responsible for the disease. In this case, only option A indicates that the child will have cystic fibrosis, which is caused by a recessive allele. Option B indicates that the child has two dominant (not recessive) alleles, while option C indicates that the child does not have the recessive allele at all. Option D indicates that the child is a heterozygous carrier, meaning they have one copy of the recessive allele and one copy of the dominant allele, and they will not have the disease. Option E refers to a condition where there are multiple alleles at a given genetic locus, but it does not relate specifically to homozygous inheritance of a recessive genetic disease.