A question in Campbell's 8th edition study guide for AP Biology says:
A multifactorial disorder _.
Answer: has a collection of symptoms traceable to an epistatic gene.
There is another answer choice which says : has both genetic and environmental causes.
Shouldn't the answer be the latter? It says the definition of multifactorial is a combination of genetic and environmental factors affect phenotype.
So is there an error in the book?
You are correct that the definition of a multifactorial disorder is one that is caused by a combination of genetic and environmental factors. However, the specific question you mentioned is asking for the option that completes the sentence "A multifactorial disorder _." The correct answer, "has a collection of symptoms traceable to an epistatic gene," is referring to a specific aspect of multifactorial disorders related to gene interactions.
Let's break it down:
1. Multifactorial disorder: This refers to a disease or disorder that is caused by multiple factors, including both genetic and environmental influences. This means that there are genetic predispositions but environmental triggers also play a role in the development or expression of the disorder.
2. Collection of symptoms: Multifactorial disorders often manifest with a variety of symptoms, which can vary in severity from person to person. These symptoms may not be the same in each affected individual due to the complex interactions between genetic and environmental factors.
3. Traceable to an epistatic gene: Epistasis refers to the interaction between genes where the expression of one gene (the epistatic gene) masks or modifies the effects of another gene (the hypostatic gene). In the context of multifactorial disorders, the symptoms can be traced back to the effects of a particular epistatic gene or genes.
So, in summary, the correct answer for this specific question is that a multifactorial disorder has a collection of symptoms traceable to an epistatic gene. However, it is important to keep in mind that multifactorial disorders are generally caused by a combination of genetic and environmental factors.