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Multiple Choice
What is the inheritance pattern of Duchenne muscular dystrophy?
A
Y-linked
B
Mitochondrial
C
X-linked recessive
D
Autosomal dominant
Verified step by step guidance
1
Understand the concept of inheritance patterns: Inheritance patterns describe how genetic traits or disorders are passed from parents to offspring. Common patterns include autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, Y-linked, and mitochondrial inheritance.
Identify the type of inheritance pattern: Duchenne muscular dystrophy is known to be an X-linked recessive disorder. This means the gene causing the disorder is located on the X chromosome, and two copies of the recessive allele are needed for females to express the disorder, while males only need one copy since they have one X chromosome.
Explore the characteristics of X-linked recessive inheritance: In X-linked recessive inheritance, males are more frequently affected than females because they have only one X chromosome. Females can be carriers if they have one affected X chromosome and one normal X chromosome.
Consider the implications for family inheritance: If a mother is a carrier of an X-linked recessive disorder, each son has a 50% chance of being affected, and each daughter has a 50% chance of being a carrier. If the father is affected, all daughters will be carriers, but sons will not be affected since they inherit the Y chromosome from their father.
Review examples and exceptions: Duchenne muscular dystrophy is a classic example of an X-linked recessive disorder. It's important to note that while most cases follow this pattern, rare exceptions can occur due to new mutations or atypical inheritance.