1. Mutations

2. Mutation – genetic mistake, some are beneficial, some are harmful
Germ mutation – affects the gamete, is passed on
Somatic mutation – affects the body cell, is not passed
Which is worse and why?
Gene mutation – affects only one gene
Chromosome mutation – affects the whole chromosome

3. Gene mutations:
1. Point mutation - One base is substituted for another

4. 2. Frameshift - one base is added or deleted, causing the rest of the protein to be wrong

5. White board question Which is worse and why: Point mutation or frameshift

6. Chromosome mutations:
Deletion – part of the chromosome is missing
Duplication – part of the chromosome is repeated
Inversion – part of the chromosome is reversed

7. 4. Translocation – a piece of the chromosome breaks off and attaches to a nonhomologous chromosome, - both chromosomes are affected

8. White board question: Which chromosome mutation is worse and why?

9. 5. Nondisjunction – chromosomes don’t separate properly during meiosis - gametes will have either too many or too few chromosomes White Board Question: Which phase of meiosis went wrong?

10. Examples of nondisjunction: Down syndrome – trisomy 21
21st chromosome has traits for mental ability
and facial features
2. Polyploidy – full extra set of chromosomes
Animals = fatal
Plants = larger fruits and vegetables

11. 3. Turner’s syndrome – monosomy 23 (X0) - sterile female
4. Klinefelter’s syndrome – trisomy 23 (XXY)
- sterile male
X chromosome is necessary for life,
it holds more genes than the Y
Y chromosome is necessary for the embryo
to develop into a male