As a Worldfamous medical doctor that dabbles in research fro

As a World-famous medical doctor that dabbles in research from time to time, you\'ve taken a recent interest in a newly discovered compound that appears to cure Sheltonitis, a terrible disease in which the affected suffers from superiority complex and other associated symptoms. However, this drug appears to work in only 33% of patients, while the remaining 67% seem completely immune to the drug. You head to your basement lab with your data to solve the mystery. You have complete family history for a large family in which every family member is affected by Sheltonitis. You\'ve constructed a family tree to discern the heritability of the drug susceptibility phenotype. The light shaded boxes indicate individuals that were NOT cured by the new drug. The clear boxes indicate individuals for whom the drug was completely effective. (Dark grey boxes indicate individuals that have not been tested.) The individual marked with the arrow is called the \'propositus\', or the individual under study. Based on this information, do you believe the drug could cure the father of the propositus? Why or why not?

Solution

All the individuals upon whom the drug was completely effective carry the dominant R allele. All those who were not cured by the drug do not have a single dominant R allele. According to the family chart, the parents of the father of the propositus are RR and rr respectively.
according to this combination, the progeny, which is the father will have Rr and thus will show positive result towards the drug, or in other words, the drug will be effective on the father of the propositus.