1. Human Heredity

2. Karyotype: picture of chromosomes

3. Most genetic disorders are caused by RECESSIVE alleles.
Cystic fibrosis- large accumulation of muscus due to lack of protein.
Phenylketonuria (PKU)- lack enzyme that converts phenylalanine to tyrosine.
Tay-Sachs- lack of enzyme that breaks down fat in the CNS
Albinism- lack of pigment in skin.

4. Cystic Fibrosis

5. Cystic Fibrosis- DON’T WRITE
Caused by a defect in a protein that results in an overproduction of muscus.
Favors bacterial infections.
1 in 20 white Americans are carriers.
1 in every 2000 children born to white americans has this disorder.
Without treatments, most children die before age 5.
With treatments, can live into 20’s+

6. Tay-Sachs- DON’T WRITE
Lack enzyme breaks down fat in the CNS- fat collects on the brain.
No treatment or cure. Most will die before the age of 6.

7. Albinism

8. Disorders caused by dominant alleles:
Huntington’s Disease
Dwarfism
Polydactylism

9. Huntington’s Disease

10. Dwarfism

11. Polydactyl- more than 5 digits on hand or foot

12. Caused by changes in DNA (mutations):
Sickle-cell Anemia: amino acid is changed in hemoglobin to give cells a sickle shape. Blocks the flow of red blood cells.

13. Sickle Cell Anemia

14. Some genetic disorders are Sex-Linked
Most commonly found in males
Mostly on X chromosome (recessive) and since males have only one X chromosome they will express the disorder more often.
Examples:
Colorblindness
Hemophilia
Muscular Dystrophy

15. DON’T WRITE
Some genes are located on the X chromosome. Females receive two alleles for these genes, but males only receive one.
If the parent is a male, the genotype is automatically known. A colorblind male has to be b, since he only has one allele and colorblindness is recessive. A normal male must then be B
Females can be heterozygous for the colorblindness trait - they are called carriers. A female can be BB - normal, Bb - carrier, or bb - colorblind

16. The following shows a cross between a normal man and a woman who is a carrier

17. colorblindess test

18. Hemophilia

19. Chromosomal Disorders
Nondisjunction: chromosomes fail to separate properly during meiosis (formation of gametes)
Down Syndrome- extra chromosome on #21 (results in total of 47 chrom)
Turner’s
Klinefelter’s

20. Down Syndrome- Extra chromosome on #21. Total of 47 chromosomes

21. Down Syndrome Karyotype

22. Klinefelter’s Karyotype XXY

23. Turner’s Karyotype Only One X

24. Pedigree—graphic representation of genetic inheritance
Pedigree—graphic representation of genetic inheritance. - Male= square - Female= circle - Shaded= has the disorder - Half shaded= carrier of disorder.