1. Mutation

2. What you need to know How alteration of chromosome number or structurally altered chromosomes can cause genetic disorders How point mutations can change the amino acid sequence of a protein

3. Mutation Mutation is a change in the genetic code Most mutations are harmless Some are harmful Few are helpful Mutations fall into 2 categories each of which have multiple variations 1.Gene mutations (aka point mutations) 2.Chromosome mutations

4. Gene/Point Mutations Mutations at a single nucleotide (base pair – bp) in a gene 1.Substitution – one bp changes letters 1.Silent – no change to protein 2.Missense – change a single amino acid (AA) into a different AA 3.Nonsense - change an AA into a stop codon Substitution

5. Gene/Point Mutations Insertion Deletion 2.Frameshift Mutations – change the reading frame (size: # of bp’s) of the gene Insertion – add 1 bp to the gene Deletion – remove 1 bp from the gene

6. Chromosome Mutations Deletion Duplication Inversion Translocation Massive mutation of part or all of a chromosome Many genes can be affected 1.Deletion 2.Duplication 3.Inversion 4.Translocation

7. Mutagenesis The creation of a mutation A.Spontaneous mutations: errors during DNA replication B.Mutagen: physical (radiation) or chemical (carcinogen) agent that triggers mutation