Gene Mutations

1. Gene Mutations Mutations: a mistake made in DNA

2. Gene Mutation • Mutation that changes one gene

3. The Rat Hid And The Cat Sat And Got Fat • Substitute a letter in the sentence makes it meaningless • The Pat Hid And The Cat Sat And Got Fat • Adding or deleting a letter is worse because ALL words change • The Rat Hix Dan Dth Eca Tsa Tan Dgo Tfa T • The Rah Ida Ndt Hec Ats Atat Ndg Otf At

4. Consequences of mutations • Amino acids make polypeptides which makes proteins • If one or more amino acids are wrong, then the organism can’t build the correct proteins

5. Gene Mutations: 2 types • 1. Point mutations: mutation that occur at one point in the sequence • 2. Frameshift mutations: mutation that shifts how all the codons are read

6. A G U C G G U G U A A G • A G U C G G U U G U A A G insertion Frameshift Mutation

7. A G U C G G U G U A A G • A G U C G G G U A A G Deletion Frameshift Mutation

8. A G U C G G U G U A A G • A G U C G G U U U A A G Substitution Point Mutation

9. Chromosome Mutations • Structure or number of chromosomes change

10. Duplication • Broken part can reattach to a sister chromatid • Normal chromosome • ABCDE FGH • Duplication of C and D • ABCDCDE FGH

11. Deletion • Normal chromosome • ABCDE FGH • Deletion of C and D • ABE FGH

12. Inversion • Broken part reattaches backwards • Normal chromosome • ABCDE FGH • Inversion of B and C • ACBDE FGH

13. Translocation • Broken part attaches to ANOTHER chromosome • Normal chromosome • ABCDE FGH • CDM NOPQR

14. When do mutations occur? • Mitosis • Meiosis

15. Mitosis • Occurs only in the individual and does NOT get passed on to offspring • Example: cancer • Common reasons for mutations: UV radiation from the sun, tanning booths, x-rays, tobacco, asbestos, benzene, chemical pesticides

16. Meiosis • Mutations that are passed on to offspring • Examples: • Sickle cell disease: substitution • Tay-Sachs: frameshift • Down syndrome: chromosome mutation on number 21