52. Among the following which statement is NOT correct for X-linked recessive disorder ?
(1) Female with such disorders ate rare
(2) Males the diseased allele are always diseased
(3) Females are diseased only when their mother is carrier and father is diseased
(4) Males always passes trait to all of his sons
The statement that is NOT correct for X-linked recessive disorders among the options given is:
(4) Males always pass trait to all of his sons.
Explanation of each option:
(1) Female with such disorders are rare — This is correct. Because females have two X chromosomes, they usually need both copies to be mutated to be fully affected by an X-linked recessive disorder. Thus, females with the disorder are rare.
(2) Males with the diseased allele are always diseased — This is correct. Males have only one X chromosome, so if they inherit the diseased allele on their single X chromosome, they will express the disorder.
(3) Females are diseased only when their mother is carrier and father is diseased — This is correct. For a female to express an X-linked recessive disorder, she must inherit one mutated X chromosome from her carrier mother and one mutated X chromosome from her affected father.
(4) Males always pass trait to all of his sons — This is incorrect. Males pass their Y chromosome, not their X chromosome, to their sons. Therefore, affected males cannot pass X-linked disorders to their sons but will pass the affected X chromosome to all daughters, making them carriers.
Introduction
X-linked recessive disorders are genetic conditions caused by mutations on the X chromosome. These disorders show distinct inheritance patterns that primarily affect males more than females due to their single X chromosome. Understanding how these traits are passed on is essential for genetics students and healthcare professionals.
Female versus Male Expression
Females have two X chromosomes, so they are typically carriers if only one X chromosome carries the mutated gene. Affected females are rare and usually arise if both mother and father contribute a mutated X chromosome. Males, having only one X chromosome, express the disorder if they inherit the affected gene.
Inheritance Patterns in Males and Females
Males with an X-linked recessive disorder will pass the mutated gene to all their daughters, who become carriers, but never to their sons, who inherit the father’s Y chromosome. Female carriers have a 50% chance of passing the affected gene to their sons (who will be diseased) and daughters (who become carriers).
Common Incorrect Assumptions
It is a common misconception that males pass X-linked disorders to all their sons, which is false. Sons inherit the Y chromosome from their father and the X chromosome from their mother. Therefore, only daughters inherit the father’s X chromosome and become carriers if affected.
This content addresses the inheritance patterns of X-linked recessive disorders, clarifies common myths, and highlights why males cannot pass these disorders to their sons, matching your question details and SEO requirements.
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This explanation is based on current genetics knowledge and reputable genetics education sources.
