Refer to the family pedigree shown here. In generation I, one parent is affected by the gene mutation and one parent isn't. In generation II, all three children are affected by the gene mutation. What can you conclude about this gene mutation?

Question

Question 8 options:

A)

This gene mutation is a recessive disorder.

B)

All children born in future generations will be affected by this disorder.

C)

The generation I mother is a carrier of this gene mutation.

D)

This gene mutation is a dominant disorder.

Answer 1

Based on the information provided, we can conclude the following:

• In generation I, one parent is affected by the gene mutation, and one parent is not.
• In generation II, all three children are affected by the gene mutation.

From this, we can infer the following:

If the affected parent must have at least one copy of the mutated gene (essentially representing either a homozygous dominant or heterozygous status) and the unaffected parent has no copies of the mutated gene, the only logical conclusion is that this gene mutation is likely a dominant disorder. This is because all offspring are affected despite one parent being unaffected.

Therefore, the correct answer is:

D) This gene mutation is a dominant disorder.