Question

X-linked recessive gene is

• A. Always expressed in male.
• B. Always expressed in female.
• C. Lethal
• D. Sub lethal

Answer 1

Answer: (A)

Always expressed in male.

A X-linked gene is present on the X chromosome. X linked recessive disorders are seen when two X-linked recessive genes are present. Since females have two X chromosomes, the X-linked recessive gene will express only if both the X chromosomes contain that gene but since males have only one X chromosome, the X-linked recessive gene is always expressed in them.

So, the correct answer is 'Always expressed in male'.