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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:
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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 Disease Some types of cancer Some forms of obesity
Notable genes on Chromosome 20: Breast Cancer Diabetes Epilepsy
Notable genes on Chromosome Y: Infertility Night 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. GENE PROTEIN
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.
ACTTGG ACTATGG ACTAGTGG ACTATGG ACTCTGG ACTATGG What happens if the gene is changed? Mutation – Change in a DNA sequence – missing base – extra base – substitute a base
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 How food is absorbed X
Notable genes on Chromosome 20: Diabetes X Insulin to control blood sugar
Basic Gene Disorder Questions • What type of genetics is it? (Dominant, recessive, sex-linked, etc.?) 2. What gene is involved? 3. On what chromosome is this gene?
Basic Gene Disorder Questions 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?
Gene Disorder ExampleTay Sachs • What type of genetics is it? (Dominant, recessive, sex-linked, etc.?) recessive 2. What gene is involved? HexA gene
Gene Disorder Example Tay Sachs 3. On what chromosome is this gene? Chromosome 15 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
Gene Disorder Example Tay Sachs 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. C. Nerve cells die.