Question

Why are sex linked recessive characters more common in the male human beings?

Hint:

Remember: Male = XY → Single X → Recessive trait expressed easily.

Answer 1

Concept: Sex-linked traits are controlled by genes located on sex chromosomes, particularly the X-chromosome.
Step 1: Chromosomal difference.

• Males have XY chromosomes
• Females have XX chromosomes

Step 2: Expression of recessive traits.

• In males, a single recessive gene on the X-chromosome is expressed because there is no corresponding allele on the Y-chromosome.
• In females, the recessive gene must be present on both X-chromosomes to be expressed.

Step 3: Result.
Thus, males are more likely to express sex-linked recessive traits such as colour blindness and haemophilia.
Step 4: Conclusion.
Therefore, sex-linked recessive characters are more common in males due to the presence of only one X-chromosome.