1. MUTATIONS

2. Mutant An organism expressing a mutated gene

3. Types of mutations Point mutations (gene mutations) change in a single DNA base pair. Frameshift mutation single base added and deleted from DNA Chromosomal mutations changes in chromosomes. Insertion, deletion, inversion and translocation.

4. Mutation A sudden genetic change

5. Gene mutations

6. Point mutations Most common Most mutations are recessive and do not show. Some result in abnormalities that show eg Albino (shows in animals but lethal in plants Some are lethal mutations and result in death.

7. Chromosome mutations

8. Usually more drastic because more genes are involved. Occur during mitosis and meiosis, chromosomes break and rejoin incorrectly. Usually lethal, therefore, not passed on to future generations. Common in plants (polyploidism) 3n, 4n, 6n, not harmful and results in bigger, better fruits.

9. Nondisjunction Occurs when homologous chromosomes fail to separate correctly during meiosis. Examples: a. Trisomy – extra chromosome, Down’s syndrome extra 21 st chromosome b. Triploidy – extra set of chromosomes 3n c. Monosomy – missing one chromosome, Turner’s syndrome one missing X chromosome

10. Somatic mutations Mutations in the body cells Not passed on to the children because they only occur in body cells.

11. Germ mutations Mutations in the germ cells (reproductive cells – gametes – eggs and sperm. Passed on to the offspring.

12. Causes of mutations Mutagenic agents are called mutagens. Mutagens disrupt normal cellular activity. Mutagens: radiation x-rays UV light Smog, smoke, industrial chemicals, air pollutants. Viruses