Mutations

1. Mutations

2. What is a mutation? • Changes in the DNA sequence that affect genetic information • Normal:Thesunwashotbuttheoldmandidnotgethishat.The sun was hot but the old man did not get his hat. • Translation changed in ribosome:t hesunw ash otbuttheoldm and idnotgish at. • Missing letter or base:the sun wshotbuttheoldm and idnotgish at.

3. Genetic mutations • Not all are harmful • Most cause little/no change • Have to be reproductive cell mutations to repeat in future generations • Somatic mutations not inheritable

4. How do mutations happen? • Environmental agents • UV light, chemicals, radiation • Meiosis • more/less chromosomes • Mistakes in DNA replication

5. What happens when there is a mutation? • The mistake can cause the cell to make an incorrect protein • see a different phenotype than normal ex. White Buffalo • If the mutation occurs in a single type of cell, • it will affect only the cell that carries it ex. Skin cells • If the mutation occurs in a sex cell, • it can be passed to the offspring and affect their phenotype • Mutations can introduce genetic variation • the change can be helpful, harmful or neither

6. Where do they happen? • Gene Mutations • replication • transcription • translation • Chromosome Structural Changes • Mitosis • Meiosis

7. Gene Mutations • Point Mutations • involve one nucleotide • single point in a DNA sequence • Substitute one base for another

8. Gene Mutations • Frameshift • insertion or deletion of a base • shifts entire sequence for translation • different group of amino acids • changes the protein function

9. Deletion- loss of all or part of chromosome - missing genes may prove fatal Duplication- segment repeated - usually harmless Chromosome Structural Changes

10. Inversion- connection broken & sequence reversed- may be fatal Translocation- non-homologous chromosomes sharing or exchanging information Chromosome Structural Changes