2.  Genetic Family Tree  Maps only one trait at a time

3.  Circle = Female  Square = Male  Shaded = has trait  Unshaded = doesn’t show trait  Half-shaded = Heterozygous  Horizontal line between male and female = parents  Vertical line = parents to kids  Each row = generation

5.  Most disorders are recessive  Cystic Fibrosis  Most common in white Americans  Defective protein in cells  Thick mucus in lungs and stomach  Treatment = physical therapy, special diets and medications

6.  Tay-Sach’s Disease  Affects brain and spinal cord  Lacking an enzyme that breaks down lipids  Lipids accumulate in brain and spinal cord  Common in Jewish-Americans and Amish

7.  Phenylketonuria (PKU)  Phenylalanine (amino acid) accumulates in body  Causes severe damage to brain  Americans from Norway or Sweden  Born normal  Infant drinks mom’s milk, which is high in phenylalanine  Causes mental retardation  PKU test given to all newborns  Treatment = special diet until brain is fully developed (early 20s)

8.  Only need to inherit disease from one parent  Huntingtons Disease  Lethal  Brain breaks down  No treatment  Doesn’t show up until 30-50