1. 4.2 - MUTATIONS (C) MCGRAW HILL RYERSON 2007

2. INTRODUCTION TEXT P.136 (C) MCGRAW HILL RYERSON 2007

3. WHAT IS A MUTATION? A gene mutation involves a change in the order of bases (A,C,T,G) that make up the gene. There are several types of gene mutation:  Deletion (base missing)  Addition (extra base added)  Substitution (one base substituted for another) Gene mutations may produce proteins that are beneficial or harmful to the organism, or may have no effect at all. Example: a particular mutated gene produces white coat Kermode bears - they occur as only a small percentage of the population (they are normally black in colour). (C) MCGRAW HILL RYERSON 2007 See pages 136 - 138 GNU License Photo

4. EFFECTS OF MUTATIONS Positive Mutations  When a gene mutation benefits the individual with the mutation  Example: Some plants have developed resistance to bacterial and fungal infections. Negative Mutations  When a gene mutation harms the individual with the mutation  Example: Sickle cell genes in affected humans cause blood cells that are abnormally shaped. Neutral Mutation  When a gene mutation has no effect on the individual  Example: The white Kermode bear  Sickle Cell Disease & Gene Therapy Video (Watch first 6 min only): https://www.youtube.com/watch?v=ujf72mjy0Bg&index=1&list=P LSnUdyQgziZunLMxACmvuxSn-A0iNZn6A https://www.youtube.com/watch?v=ujf72mjy0Bg&index=1&list=P LSnUdyQgziZunLMxACmvuxSn-A0iNZn6A (C) MCGRAW HILL RYERSON 2007 See pages 139 - 140

5. MUTAGENS & MUTATION REPAIR Mutagens are substances or factors that cause mutations Environmental mutagens include: Mercury cigarette smoke X-rays UV rays certain viruses Correcting mutations is difficult, but new techniques such as gene therapy offer hope. (C) MCGRAW HILL RYERSON 2007 See pages 141 - 143

6. MUTAGENS & MUTATION REPAIR Gene therapy is complicated and experimental:  For a defective gene to be replaced by a normal version of the gene…  A virus must be made which can carry the normal gene  The virus must be sent into the nuclei of affected cells  The replacement gene from the virus must attach to a chromosome of the target cell’s DNA  The target cell must read the newly-attached code to make the desired protein, and must make the correct amount of it  This therapy is complicated and not always successful. Sickle Cell Disease & Gene Therapy Video (Watch rest of video): https://www.youtube.com/watch?v=ujf72mjy0Bg&index=1&list=PLSnUdyQgziZunLMxACmvux Sn-A0iNZn6A https://www.youtube.com/watch?v=ujf72mjy0Bg&index=1&list=PLSnUdyQgziZunLMxACmvux Sn-A0iNZn6A General Gene Therapy https://www.youtube.com/watch?v=bLI1Gfb0ynw (C) MCGRAW HILL RYERSON 2007 See pages 141 - 143

7. (C) MCGRAW HILL RYERSON 2007 E T H I C S