Mutations

1. Mutations

2. What is a mutation? • Mutations are changes in a DNA sequences that affect the genetic information • Mutations can be caused by many factors • Some mutations can cause big problems while others are not necessarily a big deal • 2 types: gene mutations and chromosomal mutations

3. Gene Mutations • Gene mutations result from changes in a single gene • A gene mutation that affects only one nucleotide are called point mutations • Most point mutations involve substituting one nucleotide for another; this can often change one of the amino acids in a protein

4. Gene Mutations (cont.) • Frameshift mutations shift the “reading frame” of a genetic message • Frameshift mutations result in the insertion or deletion of a nucleotide • These mutations can alter the protein so that it is unable to perform its normal functions • EXAMPLE: THE FAT CAT ATE THE RAT If you take out the H of THE, it becomes TEF ATC ATA TET HER AT This deletion now makes that statement non-functional and is basically “jibberish”

6. Chromosomal Mutations • Chromosomal mutations involve changes in whole chromosomes • Usually this involves the number or structure of chromosomes • There are 4 types of mutations: deletion, duplication, inversion, and translocation

7. Chromosomal Mutations (cont.) • Deletion – loss of all or part of a chromosome • Duplication – a segment of the chromosome is repeated • Inversion – part of a chromosome becomes oriented in the reverse of its usual direction • Translocation – part of one chromosome breaks off and attaches to another nonhomologous chromosome