1. DNA and Mutations

2. Mutation Facts #1-5 Write down five facts about mutations as we go through the following videoclips Video 1 Video 2 – Repair Video 3 – Repair Addition and Deletion Mutations

3. What is a Mutation? change in the DNA code Lead to frameshifts – the message is no longer correctly passed Protein Outcomes: 1. changed – different from the original 2. no change - silent mutations 3. incomplete - amino acid is changed to a "stop" codon

4. 3 Types of Mutations: 1. Substitution - one base for another Sickle-cell Anemia GAG into GUG Valine becomes glutamic acid

5. 2. Insertion - extra bases Huntington's disease – CAG repeat fragile X syndrome – CGG repeat

6. Fragile X syndrome triplet CGG is repeated (CGGCGGCGGCGG, etc.). repeats as few as 5 or as many as 50 will not cause harm. Even 100 repeats usually cause no harm. longer repeats have a tendency to grow longer from one generation to the next (as many as 4000 repeats).

7. 3. Deletion - a section of DNA is lost, or deleted. Duchenne Muscular Dystrophy (DMD) DMD gene codes for dystrophin (protein) protein holds skeletal muscle cells together - missing in DMD

8. Mutations lead to Genetic Disorders One Wrong Letter - Tay Sachs One Wrong Letter Finding Cures is Hard - Cystic Fibrosis Finding Cures is Hard

9. Chromosome Disorders Chromosome: Coiled DNA and proteins

10. Chromosome Arrangement Called a Karyotype Receive one from mom, one from dad, they are homologs

11. Chromosome 21 “Trisomy 21’ Down Syndrome

12. Kleinfelter’s syndrome - XXY Male Develop some breast tissue Little body hair typically tall Infertility results - no sperm

13. Turner’s Syndrome – X No Y means Turner’s people are female. no ovaries develop  don’t undergo puberty and they are sterile. Hormone treatment cures all but the sterility. Other symptoms: short stature, webbed skin and low hairline at the neck

14. Mutations – good or bad? Discuss with your lab partner.

15. Reflection 1.DNA codes for proteins. If DNA is mutated, how might this cause a disease? (Connect proteins to disease). 2.How is it possible for two identical twins, with identical DNA sequences, have different traits – for instance one gets cancer and one does not.

16. What is Epigenetics?Epigenetics the study of changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the DNA