80 likes | 223 Views
Chapter 12.1: Human Traits. Pedigrees. Genetic Family Tree Maps only one trait at a time. How to Read a Pedigree. Circle = Female Square = Male Shaded = has trait Unshaded = doesn’t show trait Half-shaded = Heterozygous Horizontal line between male and female = parents
E N D
Pedigrees • Genetic Family Tree • Maps only one trait at a time
How to Read a Pedigree • 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
Recessive Disorders • 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
Recessive cont… • 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
Recessive cont… • 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)
Dominant Disorders • Only need to inherit disease from one parent • HuntingtonsDisease • Lethal • Brain breaks down • No treatment • Doesn’t show up until 30-50