Question

Based on this pedigree, what are the most likely genotypes of individuals I-1 and 1-2?

When entering the answer use AA, Aa, or aa.
Individual l-1 genotype=
Individual 1-2 genotype=

PLEASE HELP!

Answer 1

I-1 genotype = AA or Aa

I-2 genotype = aa

Step-by-step explanation:

The trait in question is autosomal and dominant. Let us assume that the trait is represented by the allele A, the alternative form would be a.

I-1 individual is affected for the disease, hence he is either true-breeding AA or heterozygous Aa.

I-2 individual is not affected for the disease, hence, she can only be aa. For an autosomal dominant trait, an individual is either affected or free from the trait. There is no chance of being a carrier. Heterozygous individuals are affected for the disease.

Therefore;

I-1 genotype = AA or Aa

I-2 genotype = aa