Mutations

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

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

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 RATIf you take out the H of THE, it becomesTEF ATC ATA TET HER AT

This deletion now makes that statement non-functional and is basically “jibberish”

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

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