1. Methods of inheritance

2. Multiple alleles Blood type gene – 3 alleles, 4 phenotypes
Alleles are IA, IB, I
Phenotypes are type A, B, AB & O
IA & IB are co dominant over O

3. Autosomal Recessive Diseases
Requires two bad alleles to show trait
Albinism
Cystic fibrosis
Phenylketonuria (PKU)
Sickle cell
Tay Sachs

4. Autosomal Dominant Disease
Huntington’s chorea
Symptoms usually don’t appear until around age 40
HH or Hh have trait
hh don’t have the trait

5. Sex – linked diseases Hemophilia Color blindness
Both are recessive so females need two bad alleles to show trait but males only need one.

6. Incomplete dominance
Snapdragon flowers get there color from co dominant alleles which also show incomplete dominance.
CR is the color allele for red
CW is the color allele for white
Heterozygous = Pink