Question

A couple, Jack and Jill, are both deaf, and each has one parent who also is deaf. Jack and Jill have 8 children: 6 boys and 2 girls, 4 of whom (1daughter and 3 sons) are also deaf?

1. identify the specific pattern of inheritance (if any) indicated for this family
2. indicate what criteria the pedigree presents that support the correct pattern of inheritance for this health problem?

Answer 1

1) X- linked dominant

2) In the pedigree, the condition isinherited in every generation, which is a dominant trait. It is also dominant because one parent from the P generation in both Jack and Jill have the allele, showing that only the certain allele needs to be present, another trait for dominance. It can be inferred that it is X- linked because 3 of the 4 sons were afflicted compared to the 1 girl, leading us to believe that it would only take one afflicted X- linked allele to cause deafness.