Types of mutations

point mutation

1. Point Mutations

2. Presented by: Muzhar Ali 4028 Ali raza 4029

3. Presented To: DR.M.Javed Iqbal Siddiqui

4. Introduction of mutations Types of mutations Chromosomal mutation Point mutation Types of point mutations Causes of mutations Contents

5. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes (eggs & sperm) and be passed to offspring

6. Types of Mutations

7. Chromosome Mutations May Involve: Changing in the number of chromosomes Lose or se gain of chromosomes e.g. Down’s syndrome . Change in the structure of chromosomes gfgfgfggfgfgfgfghgfgvggfff

8. Chromosome Mutations Down Syndrome Chromosome 21 does not separate correctly. They have 47 chromosomes in stead of 46. Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of inteligence .

9. Chromosome Mutations Due to change in structure. Deletion Inversion Translocation Nondisjunction Duplication

10. Chromosome Mutation Animation

11. Point Mutation Change of a single nucleotide Includes the deletion, insertion, or substitution of ONE nucleotide in a gene

12. Point Mutations Base Substitution Silent mutation Sense mutation Nonsense mutation

13. Mutations: Substitutions Substitution mutation GGTC A CCTCACGCCA ↓ CCAG U GGAGUGCGGU ↓ Pro- Arg -Glu-Cys-Gly Substitutions will only affect a single codon Their effects may not be serious unless they affect an amino acid that is essential for the structure and function of the finished protein molecule (e.g. sickle cell anaemia) Normal gene GGTCTCCTCACGCCA ↓ CCAGAGGAGUGCGGU Codons ↓ Pro- Glu - Glu - Cys - Gly Amino acids © 2010 Paul Billiet ODWS

14. Point Mutations Silent mutation = no change to protein AUG CGU GUA UAC GCA UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop AUG CGU GUA UAC GC U UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop

15. Point Mutation Sickle Cell disease is the result of one nucleotide substitution Occurs in the hemoglobin gene

16. Fig 4.4

17. Point Mutations Missense mutation = changes amino acid AUG CGU GUA UAC GCA UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop AUG CGU GUA UAC G U A UGC GAG UGA Met Arg Val Tyr Val Cys Glu Stop

18. Sickle cell anemia Hemoglobin protein in red blood cells strikes 1 out of 400 African Americans limits activity, painful & may die young Normal round cells Misshapen sickle cells Only 1 out of 146 amino acids

19. Point Mutations Nonsense mutation = change to STOP AUG CGU GUA UAC GCA UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop AUG CGU GUA UA A GCA UGC GAG UGA Met Arg Val Stop Really destroyed that protein !

20. Frameshift Mutations Add or delete one or more bases changes the meaning of the whole protein THE FAT CAT AND THE RED RAT RAN THE FAT CA N T AND THE RED RAT RAN THE FAT CA AND THE RED RAT RAN OR Add one ! Delete one ! Does this change the sentence? A LOT !

21. Frameshift Mutations Addition = add one or more bases AUG CGU GUA UAC GCA UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop AUG CGU GUA UAC G U CA UGC GAG UGA Met Arg Val Tyr ValMetArgVal A

22. Frameshift Mutations Deletion = lose one or more bases AUG CGU GUA UAC GCA UGC GAG UGA Met Arg Val Tyr Ala Cys Glu Stop AUG CGU GUA UAC GA UGC GAG UGA Met Arg Val Tyr AspAlaSer GA

23. Gene Mutation Animation

24. Causes of Mutations Chemical cause the mutations are called Mutagens. like Ionizing radiation Alpha, beta, gamma and cosmic rays. Nonionizing radiation Uv light, Chemical mutagens Nitrous acid, Hydroxylamine

25. Example of chemical mutations 04/12/2014 Mrs Smith: Ch13: Mutations an Chromosomal Abnormalities 31