Question

Define sex-linked Inheritance.

Answer 1

Sex-linked inheritance:

1. It is the appearance of a trait that is due to the presence of an allele exclusively on the X-chromosome or on the Y chromosome.
2. There are two types of sex-linked chromosomes: one is X linked chromosome and another is a Y-linked chromosome.
3. If one X chromosome of a female carries a recessive gene for a sex-linked trait its effect is suppressed by the corresponding dominance on another X chromosome.
4. Male has only one X chromosome so even one recessive gene on X linked trait phenotype because there is no corresponding dominant allele on the Y chromosome to suppress the effect of the recessive gene.
5. Examples of X-linked traits are Haemophilia, colour blindness, etc.
6. Examples of Y-linked traits are Turner's syndrome, hairy ears, etc.