3.20b Pedigree 2

1. We are trying to figure out whether if the affected condition within the individual is caused by the dominant or the recessive allele. 
2. If it's caused by the recessive allele it will have the genotype dd
3. If it's caused by the dominant allele it will either have the genotype Dd or DD. 
4. The affected condition is caused through the recessive allele as shown in the example in the diagram.