The document explains sex-linked inheritance, focusing on x-linked dominant and recessive inheritance patterns and their effects on males and females. It details how traits are passed down, especially under conditions when either parent is a carrier of a mutated gene. Additionally, it mentions y-linked inheritance, which is rare and specifically affects males, occurring from father to son.

1. Sex-Linked Inheritance

2. Sex-Linked Inheritance
• It is the inheritance of a trait (phenotype)
that is determined by a gene located on
one of the sex chromosomes

3. X-Linked Dominant Inheritance
• Dominant gene is carried on the X-gene
• Males – get their X-Chromosome from
their mother
• Females – get their X-Chromosome from
both of their parents

4. X-Linked Dominant Inheritance
• If the mother is a carrier of the mutated
gene
• 50% of the son or/and daughter will be
affected
• 50% of the son or/and daughter will be
normal

6. X-Linked Dominant Inheritance
• If the father is a carrier of the mutated
gene
• 100% of his daughter will have the
disorder
• 0% of his son will have the disorder

8. X-Linked Dominant Inheritance
• If both parents are a carrier of the
mutated gene
• 100% of his daughter will have the
disorder
• 50% of his son will have the disorder
• 50% of his son will be unaffected or
normal

9. X-Linked Recessive Inheritance
• A mode of inheritance on the X-
Chromosome that causes the phenotype
to be expressed
• Female carriers have only copy of the
gene and usually don’t express the
phenotype

10. X-Linked Recessive Inheritance
Examples of X-Linked Recessive
Inheritance:
•Color Blindness
•Haemophilia
•Becker’s Muscular Dystrophy
•Hunter’s Syndrome

11. Y-Linked Inheritance
• Holandric Inheritance
• Y-Chromosome is small and doesn’t
contain numerous genes
• Y-linked diseases or disorder are very
rare
• It occurs between fathers and his son/s