1. Mutations! THIS PRESENTATION IS ON MY WEBSITE

2. Review yesterday! Be ready to give answers to 15, 16, and 17 from yesterday…

3. What is a gene? Discuss what you have heard, be ready to share. ◦A sequence of DNA that codes for a specific protein (or proteins) associated with a trait, characteristic, or genetic condition What do you know about mutations? Discuss, be ready to share.

4. Gene Mutations Gene mutations: occur in a single gene, usually during mitosis or meiosis ◦Gene mutations- when DNA polymerase does its job incorrectly in interphase ◦“Point” gene mutations – occur in one/few bases (3 types) ◦1) Insertion ◦Adding a base/bases ◦2) Deletion ◦Removing a base/bases ◦3) Substitution ◦Swapping out a base/bases ◦Point mutations: no effect, positive effect on trait, or negative effect on trait. ◦Example mutation today: hemoglobin. What do you know about hemoglobin?

5. Example mutation - hemoglobin What do you know about hemoglobin? Discuss, be ready to share. ◦Hemoglobin carries oxygen in red blood cells (don’t need to takes notes on this!) ◦“HBB” gene for hemoglobin on chromosome #11 (out of 23) ◦HBB – 1600 base pairs, 3 exons ◦mRNA with introns, promoter, TATA removed: 444 base pairs ◦Mutant version of HBB can causes red blood cells to clump. ◦One bad gene = some clumping of red blood cells ◦2 bad genes = “sickle cell anemia” ◦http://cbm.msoe.edu/includes/swf/NewestSickleCell.swfhttp://cbm.msoe.edu/includes/swf/NewestSickleCell.swf

6. Typical hemoglobin Transcribe and translate this portion of the “typical” HBB gene: ◦GACTGAGGACTCCTC ◦mRNA: CUGACUCCUGAGGAG ◦Leucine-Threonine-Proline-Glutamic acid-Glutamic acid

7. Deletion and insertion mutations (using hemoglobin as an example) Transcribe and translate this portion of the mutated HBB gene: ◦GCTGAGGACTCCTC ◦mRNA: CACUCCUGAGGAG ◦Arginine-Leucine-Leucine-Arginine -…and extra bases (two diff a.a…) Example of a “frameshift” – all codons are “shifted” Deletion mutations (frameshift): Usually result in different primary structure  major protein problems Insertion mutations (frameshift): Usually result in different primary structure  major protein problems

8. Substitution mutations (using hemoglobin as an example) Transcribe and translate this portion of the mutated HBB gene: ◦GACTGAGGACTTCTC (hint: only one base changed…) ◦mRNA: CUGACUCCUGAAGAG ◦Leucine-Threonine-Proline-Glutamic acid-Glutamic acid ◦Substitution mutations ◦Might not have an effect on the protein (don’t matter) ◦Could be harmful (see next slide) ◦Could put a stop codon in the wrong place ◦Could code for an incorrect amino acid with big consequences

9. Substitution mutations - 2 (using hemoglobin as an example) Transcribe and translate this portion of the mutated HBB gene: ◦GACTGAGGACACCTC (hint: only one base changed…) ◦mRNA: CUGACUCCUGUGGAG ◦Leucine-Threonine-Proline-Valine-Glutamic acid ◦This single amino acid change completely changes the protein! ◦http://www.rpc.msoe.edu/cbm/resources/NewestSickleCell.swfhttp://www.rpc.msoe.edu/cbm/resources/NewestSickleCell.swf

10. Chromosomal mutations (in tonight’s reading) Mistakes in large portions of an entire chromosome – BIG consequences. Paper models returned!