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Multiple Choice
Which of the following statements about an X-linked dominant disease is true?
A
The disease is more common in males than females.
B
Affected males will pass the disease to all of their daughters.
C
The disease skips generations in a family.
D
Affected females cannot pass the disease to their sons.
Verified step by step guidance
1
Understand the concept of X-linked dominant inheritance: In X-linked dominant diseases, the gene causing the disease is located on the X chromosome. Dominant means that only one copy of the gene is needed for the disease to manifest.
Consider the inheritance pattern: Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). An affected male will have the disease-causing gene on his single X chromosome.
Analyze the transmission from affected males: Since males pass their X chromosome to their daughters, all daughters of an affected male will inherit the X chromosome with the disease-causing gene, making them affected.
Evaluate the transmission from affected females: Affected females have one affected X chromosome. They can pass either the affected or the unaffected X chromosome to their children, meaning they can pass the disease to both sons and daughters.
Review the statement about skipping generations: X-linked dominant diseases do not typically skip generations because the presence of the dominant allele on the X chromosome will manifest in every generation where it is present.