Question

Which of the following scenarios describes a Polygenic condition?

A:	Abby suffers from mild symptoms of HAP disorder, but her son suffers from severe symptoms
B.	Beth should show symptoms of diabetes, but she doesn't
C.	Inheritance of mutated copies of the PA2, PA3, or PA4 gene all cause liver disease, but they each alter different proteins
D.	People affected by FAL disorder have 5 different mutations, but suffer from the same symptoms
E	Sarah has inherited a mutated copy of the ALI gene and suffers from migraines, stomach ulcers, and high cholesterol

Answer 1

Polygenic trait refers to the trait that is coded by several genes.

A) HAP disorder refers to Hospital-acquired pneumonia. It is not a genetic disorder. It is a disease caused by infections that arise out of infections in hospitals.

B) Diabetes symptoms are not being exhibited. This could be due to several factors like the day of investigation is too early etc. and this is not a polygenic trait.

C) PA2, PA3, and PA4 are different genes. These are encoding for different proteins. However, the mutations in all of them result in liver disease. Hence, the inheritance of these genes is a polygenic inheritance condition.

D) The FAL disorder is due to 5 different mutations. However, all of these result in the same symptoms. Hence, the different mutations are coding for the same phenotype. However, these mutations might be present on the same gene. Hence, this is not an instance of polygenic inheritance.

E) Here a single copy of the ALI gene is giving rise to a repertoire of phenotypes. Thus, this is an instance of pleiotropic inheritance and not polygenic inheritance.

Therefore, the correct answer is C.