AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

THE HUMAN GENOME

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A child is diagnosed with a rare disease. Neither parent has the disease. How did the child inherit the disorder?
A
The disorder is dominant and carried by a parent.
B
The disorder is recessive and carried by both parents.
C
The disorder is sex-linked and inherited only from the father.
D
A mutation in the child occurred.
Explanation: 

Detailed explanation-1: -Dominant inheritance means an abnormal gene from one parent can cause disease. This happens even when the matching gene from the other parent is normal. The abnormal gene dominates. This disease can also occur as a new condition in a child when neither parent has the abnormal gene.

Detailed explanation-2: -In some cases, an affected person inherits the condition from an affected parent . In others, the condition may result from a new variant in the gene and occur in people with no history of the disorder in their family. In autosomal recessive inheritance, variants occur in both copies of the gene in each cell.

Detailed explanation-3: -You have a 50% (1 in 2) chance of inheriting one abnormal gene.

Detailed explanation-4: -Autosomal recessive inheritance is a way a genetic trait or condition can be passed down from parent to child. A genetic condition can occur when the child inherits one copy of a mutated (changed) gene from each parent. The parents of a child with an autosomal recessive condition usually do not have the condition.

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