1. Pedigrees

2. Pedigrees
Pedigrees show how a trait/disorder is passed from one generation to the next
Symbols:
Squares = males (XY), circles = females (XX)
Horizontal lines connect breeding couples
Vertical lines connect parents to children
Shading (filled in) = individual has the trait
No shading = individual does not have the trait
Half shading or a dot = a carrier
A diagonal line means death
Roman numerals show generations
Numbers assign an individual to a generation

3. Interpreting Pedigrees
Trait is dominant or recessive?
Skips a generation = recessive
Every generation = dominant
Trait is autosomal or sex linked?
Affects ♂ and ♀ equally → autosomal
Affects ♂ more than ♀ → sex-linked
Females tend to “carry” a trait and affect their sons
Females get the trait from affected father and carrier/affected mother
Affected males got it from their mother and give it to their daughters to “carry.”

4. Autosomal Dominant aa Aa aa Aa aa Aa aa Aa or AA Aa aa aa Aa Aa
Autosomal or Sex-linked? ____________________
Is this dominant or recessive? ____________________
Assign genotypes to the pedigree to show the inheritance pattern
Dominant

5. Sex-linked Recessive XBY XBXb XbY XBXb XBY XBXb XBXb XbY XBY XbY XBXb
Autosomal or Sex-linked? ____________________
Is this dominant or recessive? ____________________
Assign genotypes to the pedigree to show the inheritance pattern
Fill in what you know first!
Recessive

6. Pedigree with half-shading to show carriers