Dominant vs Recessive Inheritance Disorders

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Questions and Answers

In a dominant inheritance disorder, if a person has one mutated allele and one healthy allele for a gene, what determines whether the person will express the disorder?

The healthy allele must be completely non-functional.
The expression of the mutated allele depends on environmental factors.
The mutated allele is dominant and its effect is expressed. (correct)
The mutated allele is recessive and requires a second copy to be expressed.

For a recessive inheritance disorder to be expressed, what genetic condition must be present?

The individual must have two copies of the mutated allele. (correct)
A single mutated allele is sufficient for expression.
The individual must have one mutated allele and one dominant allele.
The individual must be a carrier of the mutated allele.

How does the timing of onset typically differ between recessive inheritance disorders (RID) and dominant inheritance disorders (DID)?

RID typically appear later in life, while DID appear earlier.
The timing of onset is unpredictable for both RID and DID.
Both RID and DID appear at the same age.
RID typically appear earlier in life, while DID appear later. (correct)

Which is a key characteristic distinguishing dominant inheritance disorders (DID) from recessive inheritance disorders (RID)?

In DID, the mutated allele results in a gain of function, while in RID, it results in a loss of function. (B) Signup and view all the answers

What is the significance of 'penetrance' in the context of genetic disorders?

It refers to the percentage of individuals with a specific genotype who also exhibit the associated phenotype. (C) Signup and view all the answers

How does 'reduced penetrance' manifest in individuals carrying a disease-causing genotype?

They do not express the disease phenotype despite having the disease-causing genotype. (A) Signup and view all the answers

What is 'non-penetrance' in the context of genetics?

The absence of a defective gene, resulting in a normal phenotype. (D) Signup and view all the answers

How does pleiotropy manifest in genetic disorders?

A single gene mutation affects multiple organ systems. (D) Signup and view all the answers

In genetic terms, what does 'variable expressivity' refer to?

The range of signs and symptoms that can occur in different people with the same genetic condition. (C) Signup and view all the answers

Distinguish between reduced penetrance and variable expressivity in the context of genetic disorders.

Reduced penetrance refers to the percentage of individuals with a specific genotype who also exhibit the associated phenotype, while variable expressivity refers to the range of signs and symptoms that can occur in different people with the same genetic condition. (A) Signup and view all the answers

If a genetic mutation results in a protein performing a new function, this is best described as:

Gain of function (C) Signup and view all the answers

How do 'real carriers' relate to Dominant Inheritance Disorders (DID)?

Individuals cannot be carriers of a DID; instead, people have different levels of penetration. (B) Signup and view all the answers

What is true of Recessive Inheritance Disorders (RID)?

People can be carriers of RID but not experience the disorder itself. (D) Signup and view all the answers

What is one major difference between Recessive Inheritance Disorders (RID) and Dominant Inheritance Disorders (DID)?

RID are usually more severe or dangerous than DID. (A) Signup and view all the answers

A person has a mutated gene and it is expressed. What is this called?

Penetration (D) Signup and view all the answers

Flashcards

Dominant Inheritance Disorder

A genetic disorder where a person has both a mutated and healthy allele, but the mutation is expressed.

Recessive Inheritance Disorder

A genetic disorder where the mutated allele is recessive, requiring two copies for the mutation to be expressed.

Dominant Inheritance Disorders (DID)

Requires only 1 defective allele for the mutation to be expressed; appears later in life, and the mutated allele experiences a gain in function.

Recessive Inheritance Disorders (RID)

Requires 2 mutant alleles in order to be expressed; appear early in life, are usually more severe, and the mutated gene loses its function.