1. Human Heredity and Single Gene Disorders

2. Autosomal? These types of gene disorders are only found in chromosome pairs 1-22

3. Gene Mutations The instructions in 1 out of the 24,000 genes gets messed up

4. Gene Mutations Insertion, deletion or substitution of 1 or more bases changes amino acids and makes the protein incorrectly “Normal” DNA sequenceMutated DNA sequence DNA: TCACGATTT mRNA: AGUGCUAAA SerAlaLys DNA: TCATGATTT mRNA: AGUACUAAA SerThrLys

5. Example: Cystic fibrosis (1 in 2000 Europeans) Gene on chromosome 7 Normal dominant allele (N) makes a protein to transport chloride ions across cells Mutated recessive allele (n) makes a protein that does not transport chloride ions across cell Result= mucus that clogs lungs and pancreas=shortened life expectance to early adulthood NN=normal Nn=normal nn=cystic fibrosis

6. Example: Tay-Sachs disease (1 in 600 Jews) Gene on chromosome 15 Normal dominant allele (N) makes a protein that is an enzyme which breaks stuff down in lysosome’s Mutated recessive allele (n) makes an enzyme that does not work Result= build up of waste causes nerve cells to die= brain damage and death in early childhood NN=normal Nn=normal nn=Tay-Sachs

7. Example: Sickle cell anemia (1 in 500 African Americans) Gene on chromosome 11 Normal dominant allele (N) makes a protein that carries oxygen in red blood cells Mutated recessive allele (n) makes a protein that causes the cell to change shape Result= Cylinder shaped red blood cells clog blood vessels= damaged organs due to lack of oxygen NN=normal Nn=Normal nn= sickle cell anemia

9. Example: Huntington’s Disease (1 in 10,000) Gene on chromosome 4 Normal recessive allele (n) makes a protein that helps move vesicles in nerve cells Mutated dominant allele (N) makes a damaged protein which causes defected nerves in brain Result=at middle age loss of body function and death NN=Huntington’s disease Nn=Huntington’s disease nn= normal

10. Example: Hutchinson Giford Progeria Syndrome (1 in 4-8 million new borns) Gene on chromosome 1 Normal recessive allele (n) makes a protein that builds the nucleus (nuclear envelope) Mutated dominant allele (N) makes a damaged protein that makes the nucleus unstable and misshapen Result=The unstable nucleus becomes damaged over time, leading to early death of cells and early death of the individual NN=Hutchinson Gilford diseaase Nn=Hutchinson Gilford disease nn= normal