Genetic Disorders – Gene Disorders

What is a gene? Gene – Sequence of DNA bases that code for a trait (blueprint)

Where are genes stored? Genes are found on chromosomes. Each chromosome has its own set of genes.

Notable genes on Chromosome 18: Parkinson DiseaseSome types of cancer Some forms of obesity

Notable genes on Chromosome 20: Breast CancerDiabetes Epilepsy

Notable genes on Chromosome Y: InfertilityNight blindness Inability to make testes

How does DNA sequence lead to a trait? In order to make a trait, a cell uses the gene information to build a protein. GENEPROTEIN

What are some examples of proteins? -Hair -Fingernails, horns, antlers - Hemoglobin - Enzymes to digest food - Antibodies to fight disease

What happens if the gene is changed? As with a blueprint, if you change the directions you change the product.

What happens if the gene is changed? Mutation – Change in a DNA sequence – missing base – extra base – substitute a base ACTATGG ACTTGG ACTATGG ACTAGTGG ACTATGG ACTCTGG

Mutations Part 2 Everyone has a complete set of genes (eye color, blood type, tongue rolling, etc.) but which version you inherited makes a big difference. In reality there is no “cancer gene”. Instead, there are versions of checkpoint protein genes that don’t control cell cycle properly.

Notable genes on Chromosome 18: Some forms of obesity X How food is absorbed

Notable genes on Chromosome 20: Diabetes X Insulin to control blood sugar

Basic Gene Disorder Questions 1.What type of genetics is it? (Dominant, recessive, sex-linked, etc.?) 2. What gene is involved? 3. On what chromosome is this gene?

4. What protein does this gene make? 5. What is this protein supposed to do? 6. Since this protein isn’t working right, how does this lead to the symptoms? Basic Gene Disorder Questions

Gene Disorder Example Tay Sachs 1.What type of genetics is it? (Dominant, recessive, sex-linked, etc.?) recessive 2. What gene is involved? HexA gene

Gene Disorder Example Tay Sachs Chromosome On what chromosome is this gene? P’s and Q’s? -Different ends of chromosome -#’s show distance from centromere

Gene Disorder Example Tay Sachs 4. What protein does this gene make? Part of hexosaminidase

5. What is this protein supposed to do? A. Found in lysosomes of brain and spinal cord cells B. Digests fats called gangliosides Gene Disorder Example Tay Sachs

6. Since this protein isn’t working right, how does this lead to the symptoms? A. Hexosaminidase can’t break down gangliosides. B. Gangliosides build up to toxic levels. Gene Disorder Example Tay Sachs C. Nerve cells die.