Sex linkage inheritance

Autosomal Dominant Pattern:

• BOTH male and females can be affected

• ALL affected individuals have at least ONE affected parent

• Transmission can be from fathers to daughters and sons, or from mothers to daughters and sons

• Once the trait disappears from a branch of the pedigree, it does NOT reappear

Autosomal Recessive Pattern:

• BOTH males and females can be affected

• Two UNAFFECTED parents can have an AFFECTED child

• ALL the children of the two persons with the condition must also show the condition

• The trait may disappear from a branch of the pedigree, but REAPPEAR in later generations

• Over a large number of pedigrees, there are approximately EQUAL numbers of affected females and males

X-Linked Dominant Pattern:

• MALE with trait passes it on to ALL daughters and NONE of the sons

• FEMALE with trait may pass it it on to BOTH her daughters and her sons

• EVERY affected person has at least one parent with the trait

• If the trait disappears from a branch of pedigree, it does NOT reappear

• Over a large number of pedigrees, there are more affected females than males

X-Linked Recessive Pattern:

• ALL the sons of a female with trait are affected

• ALL daughters of a male with trait are CARRIERS but do not SHOW the trait; trait can appear in their sons

• None of the sons of a male with the trait and an unaffected female show the trait, unless the mother is carrier

• ALL children of two individuals with the trait ALSO show the trait

• In large samples, more males than females show the trait