The following question refers to the pedigree chart in the figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.

What is the likelihood that the offspring of IV-3 and IV-4 will have the trait?

Question

The following question refers to the pedigree chart in the figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.

What is the likelihood that the offspring of IV-3 and IV-4 will have the trait?

Quizplus · Accepted Answer

IV-3 is unaffected and thus does not carry the dominant trait W. IV-4 is affected and must carry at least one copy of the W allele. Therefore, the probability of their offspring inheriting the W allele from IV-4 is 1/2. The probability of their offspring inheriting the W allele from IV-3 is 0. Therefore, the likelihood of their offspring having the trait is 50%.

The Following Question Refers to the Pedigree Chart in the Figure