Question

how to look for genetic patterns in a pedigree

Answer 1

Autosomal recessive inheritance -

• Trait often skips generation
• Almost equal number of affected males and females
• If both parents are affected, all children should be affected
• Unaffected people mating with affected one, all children are unaffected. If one child is affected shows unaffected parent is heterozygous
• affected individuals have unaffected parents

Autosomal dominant inheritance -

• Trait should not skip generation
• Affected person mating an unaffected person produce 50% affected offspring, affected person is heterozygous
• distribution of trait among male and female will be equal

Sex linked or X-linked recessive inheritance-

• Most affected individuals are males
• Affected male result from affected mother or a carrier
• Affected female come from affected father and affected or carrier mother
• son of affected female will be affected
• Half the sons of carrier will be affected

Sex-linked or X-linked dominant inheritance -

• Affected males come from affected mothers
• Halif of the children of affected heterozygous female are affected
• Affected females come from affected mother or father
• All the daughter but not sons of an affected father will be affected

Y-linked inheritance -

• males are affected, that have affected father
• All sons of affected father are affected