brief overview of Mutation.
- 2. WWhhaatt AArree MMuuttaattiioonnss?? • 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
- 5. Gene Mutations • Change in the nucleotide sequence of a gene • May only involve a single nucleotide • May be due to copying errors, chemicals, viruses, etc.
- 6. At nucleotide level : 1. Insertion (One or more nucleotides may be inserted in a DNA sequence) 2. Deletion (One or more nucleotides may be deleted from DNA sequence) 3. Indels (insertions of some bases and deletions of others) 4. Transition (CT or TC ---or AG or GA substitution) 5. Transversion (GC or CG ---or AT or TA substitution) These mutations can be anywhere in the genome, coding or non-coding
- 7. Mutations in coding region by effect
- 8. Point Mutation • Change of a single nucleotide • Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
- 9. Point Mutation • Sickle Cell disease is the result of one nucleotide substitution • Occurs in the hemoglobin gene
- 10. Chromosome Mutations • May Involve: – Changing the structure of a chromosome – The loss or gain of part of a chromosome
- 11. Chromosome Mutations • Five types exist: – Deletion – Inversion – Translocation –Nondisjunction – Duplication
- 12. Deletion • Due to breakage • A piece of a chromosome is lost
- 13. Inversion • Chromosome segment breaks off • Segment flips around backwards • Segment reattaches
- 14. Duplication • Occurs when a gene sequence is repeated
- 15. Translocation • Involves two chromosomes that aren’t homologous • Part of one chromosome is transferred to another chromosomes
- 16. Translocation
- 17. Nondisjunction • Failure of chromosomes to separate during meiosis • Causes gamete to have too many or too few chromosomes • Disorders: – Down Syndrome – three 21st chromosomes – Turner Syndrome – single X chromosome – Klinefelter’s Syndrome – XXY chromosomes
- 19. When it is sufficiently common in a population that it cannot be explained by recurring mutation. It is a polymorphism WHEN IS A MUTATION NOT A MUTATION?
- 20. SNP • Single nucleotide polymorphisms (SNP) ACGGGGGTTTCCC ACGGGGGTTTCCG Coding SNPs Non coding SNPs A SNP can change recognition sequence in a DNA for a Restriction enzyme, so that it can no longer be recognized by it A SNP can create a new site for Restriction Enzyme • Restriction fragment length polymophisms (RFLP) Length of a restriction fragment changes. Detected by Southern blotting and now typed by PCR
- 21. Thanku : )