1. Mutation!!!

2. Causes: mutagens Biological viruses disrupt instructions stored in genes by attaching to the DNA and interfering As a result things can get misread or copied incorrectly Other examples are: –Cigarette smoke –Radiating (x rays or UV rays) –Mercury Mutagens can upset the life cycle of a cell and even cause Cancer

3. Gene mutations A gene mutation is a change in the order of the A, G, C and T bases in a gene This can result from  a base left out of sequence (deletion)  an extra base added (addition)  one base substituted for another (substitution) Gene mutations can be positive, negative or neutral Some mutations can be passed on to offspring

4. Spirit bear Most black bears are black (which I am sure you guessed) There is a mutation in 1 out of 10 of the population of kermode bears (a subspecies of black bears) that turns the coat white This is the result of amutation on just ONE base in the gene for coat colour To have a white coat, both parents must carry the altered gene

6. The spirit bear is an example of a neutral mutation The mutation does not appear to help or hinder the organism that has it The most common types of gene mutations are neutral mutations

7. Now do the activity on pg 137 in your books :) You have 15 minutes

8. Positive mutation HIV is a dangerous virus that will lead to AIDS There is still no known cure or vaccine However, a small percentage of the population has a mutation that makes them resistant to HIV This is the result of a mutated gene that contains the instructions for a protein that prevents HIV infection

10. Negative Mutations Cystic fibrosis is a genetic disease caused by a mutation In cystic fibrosis, mucus builds up because of a malfunctioning protein This leads to difficulty breathing, lung infections and can cause death Daily antibiotics and physical therapy are needed to prevent lung infections

11. Now for a video on a mutation that is both negative...and positive! Sickle cell anemia is a “negative” mutation that affects the hemoglobin in red blood cells. It is the result of a substitution of the base A for the base T Sickle cell anemiaSickle cell anemia video