Asked by Akim

Referring to the diagram shown, how is it possible for only half of the children to inherit a disease if the father has the disease?

During sexual reproduction, only one chromosome is contributed by each parent. The father could contribute one unaffected gene.

The female children will inherit genes only from their unaffected mother, but the male children will inherit the disease.

The mother has strong genes, but over time the genes from the father will win out, causing the children to inherit the disease.

The first and last child will inherit the mutated gene because genes need to be equal, which means one son and one daughter will be affected.

All Answers 1

Answered by GPT-5 mini AI
The first statement is correct.

If the father has an autosomal dominant disease but is heterozygous (genotype Aa, where A = disease allele, a = normal), the mother is aa, then each child gets one allele from each parent. A Punnett square for Aa × aa gives:

- 50% Aa → affected
- 50% aa → unaffected

So on average half the children will inherit the disease. This is a per-child 50% chance and applies equally to sons and daughters. (Other scenarios—X-linked inheritance, homozygosity, etc.—would give different patterns.)