Question

Which of the following is the most common effect of a disease causing mutation on a protein?

A Loss of function
B Gain of function
C Heterochronic expression
D Ectopic expression
E Dominant negative

Answer 1

The most common effect of a disease-causing mutation on a protein is a loss of function, which can lead to partial or complete non-functionality of the protein, affecting the organism's health.

Step-by-step explanation:

The most common effect of a disease-causing mutation on a protein is loss of function. Mutations can cause errors in protein sequences, leading to proteins that are partially or completely non-functional. For example, proteins synthesised with incorrect amino acid sequences can affect their structure and enzymatic activities. As a result, this may lead to an accumulation of toxic substrates or a deficit of critical products necessary for normal body functions, as seen in conditions like sickle cell disease and galactosemia. A gain of function mutation or a dominant negative mutation are less common but can have severe effects, such as constitutive activation of proteins in the case of some oncogenes or competitive inhibition of normal protein function.