Which inheritance pattern is described as being located on the X chromosome and often expressed in males?

Which inheritance pattern is described as being located on the X chromosome and often expressed in males?

• A. Autosomal recessive disease
• B. X-linked disorders
• C. Autosomal dominant disease
• D. Mitochondrial inheritance

Answer: (B)

X-linked inheritance involves genes on the X chromosome. Since males have only one X (and one Y), a single mutant allele on that X will typically be expressed, so X-linked conditions often appear in males. Females would usually need two mutated copies to show the trait (in classic X-linked recessive disorders), or may be affected if the mutation is X-linked dominant or due to skewed X-inactivation. This distinguishes it from autosomal patterns, which are on the non-sex chromosomes and affect sexes more equally, and mitochondrial inheritance, which is passed from mothers through mitochondrial DNA. So this description best fits X-linked disorders.

X-linked inheritance involves genes on the X chromosome. Since males have only one X (and one Y), a single mutant allele on that X will typically be expressed, so X-linked conditions often appear in males. Females would usually need two mutated copies to show the trait (in classic X-linked recessive disorders), or may be affected if the mutation is X-linked dominant or due to skewed X-inactivation. This distinguishes it from autosomal patterns, which are on the non-sex chromosomes and affect sexes more equally, and mitochondrial inheritance, which is passed from mothers through mitochondrial DNA. So this description best fits X-linked disorders.