1. MUTATIONS pp. 224-226, 231

2. MUTATION  A change in a genetic trait  Either 1) chromosomal or 2) gene mutation  Germ cell (gametes) or somatic cell (body)  Germ cell mutations can be inherited and somatic cell mutations result in cancers  Can be lethal (deadly) even before birth

3. CHROMOSOMAL MUTATIONS

4. DELETION  loss of a piece of chromosome EX. Cri du chat &Wolf- Hirschhorn syndrome

5. INVERSION AND TRANSLOCATION  Inversion: chromosome breaks off and reattaches in reverse  Translocation: piece breaks off and attaches to another * No problems in an individual since all genes are intact but there are problems with crossing over during meiosis

6. NONDISJUNCTION  failure of a chromosome to separate from its homologous chromosome  Trisomy - one too many chromosomes (2n=47) EX: Down Syndrome, Kleinfelter’s Syndrome (XXY)  Monosomy - only one of a homologous pair (2n=45) EX: Turner Syndrome (X)

7. KARYOTYPE: photo of chromosomes

8. GENE MUTATION  A change in the genetic code of one gene  Only one trait is affected Point mutation: substitution, addition, or removal of a nucleotide

9. SUBSTITUTION  results in new codon (could be different, same amino acid or stop) EX. Sickle cell anemia

10. FRAME SHIFT MUTATION  removal or addition of a nucleotide causes shift in entire sequence