Nail–patella syndrome is an autosomal disorder affecting the shap...

Question

Nail–patella syndrome is an autosomal disorder affecting the shape of nails on fingers and toes as well as the structure of kneecaps. The pedigree below shows the transmission of nail–patella syndrome in a family along with ABO blood type.

Is nail–patella syndrome a dominant or a recessive condition? Explain your reasoning.

Accepted Answer

Everyone. Let's take a look at this question together. Huntington's disease is caused by a mutation in a single gene. This is a genetic disorder that affects the brain. And if an individual has one copy of the mutated gene, they will have the disease. The mutated gene is passed on from parent to child. What is the probability of each of their Children developing the condition if one parent has the mutated gene? So from the information provided in the question, we know that if an individual has one copy of the mutated gene, they will have the disease. So that means that only one mutant copy is needed two express the disease, which as we know, when only one copy of the mutated gene is required in order to express the disease, it is a dominant jean. And since that mutated gene is then passed on from parent to child, the probability of each of their Children developing the condition. If only one parent has the mutated gene, we know is 50% or answer choice B the correct answer because in the case of this disease being dominant and only requiring one mutant copy, there is that 50% chance that you would inherent the mutated or the normal dean. Since there are only either the mutated or the normal gene, you either inherit the mutated or the normal. So there is that 50% chance that you inherit the mutated gene, which means that the probability of their child developing the condition is answer choice. B50%. I hope you found this video to be helpful. Thank you and goodbye.

Key Concepts

Autosomal Dominance and Recessiveness

Pedigree Analysis

ABO Blood Type Genetics

Watch next