Question

For each pedigree below determine the most likely mode of inheritance and label each individual with a genotype. If you know they have a dominant phenotype, but don’t know the genotype, then label them with both possibilities. Please use the alleles A and a for autosomal modes of inheritance and XA, Xa and Ya for any types of sex-linkage (note: an “a” is only on the Y if the trait is Y-linked). Modes of inheritance are autosomal dominant, autosomal recessive, sex-linked dominant, sex-linked recessive and Y-linked. For each pedigree determine if alternative modes are possible.

Answer 1

The mode of inheritance is Autosomal Dominant.

There is no escaping generation. if either of the parents have the disease, it is inherited to the offsprings. There are no offsprings who are affected but their parents are not.

Autosomal recessive is not possible since a single affected parent is able to pass the disease to offsprings.

Y-linked inheritance is not possible since female are also affected.

Sex-linked inheritance is not possible because both female and male are equally affected. Sex-linked recessive is not possible because both the affected parents do not pass the disease to thier male offspring (see 5th generation right hand side extreme). Also, Sex-linked dominant is not possible.