1. Chapter 11 Genetic Disorders
Biology
Chapter 11
Genetic Disorders

2. Human Genetic Disorders
Cystic Fibrosis
Most common in whites
1 in 20 people are a carrier
Mucus clogs lungs
Failure of chloride ion transport protein
Recessive

3. Human Genetic Disorders
Huntington’s Disease
Dominant
Symptoms usually do not appear until later in life
Brain cells deteriorate

4. Human Genetic Disorders
Sickle Cell Anemia
Mostly in African Americans; 1 in 500
Caused by a single amino acid change in the 574 aa protein.
Instead of glutamine, there is valine
This disorder prevents hemoglobin (carrier of oxygen) to work properly

5. Human Genetic Disorders
Hemophilia
Sex-linked recessive (on the X chromosome)
Failure of blood to clot
Missing a clotting factor in the blood

6. Human Genetic Disorders
Color Blindness
Sex-linked recessive
Inability to distinguish between colors (red and green look brown)
Missing a receptor to code for the colors

7. Human Genetic Disorders
Trisomy – Presence of three of one kind of chromosome
Karyotype – Map (picture) of human chromosomes

8. Human Genetic Disorders
Down Syndrome
Recessive
Have extra copy of 21st chromosome
Caused by nondisjunction (failure of chromosomes to separate during meiosis) or by part breaking off and fusing to # 14

9. Human Genetic Disorders
Prevention
Genetic counseling –
Amniocentesis: Sample of the fluid surrounding a fetus is extracted and examined.
Can obtain a karyotype

10. Human Genetic Disorders
Prevention
Usually need an ultra sound before amniocentesis (after 14th week)
Chorionic Villus Biopsy: Can be performed in 9th week.
Take cells from the chorion, tissue where fetus is linked to mother.
Can analyze and determine a karyotype