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POINT MUTATIONS

POINT MUTATIONS. Not like X-Men. MUTATION. Any change in the genetic sequence (DNA) that affects the genetic information. POINT MUTATIONS. Occurs at 1 single point in DNA These could cause one amino acid to change, which would change the protein that is being produced. POINT MUTATIONS.

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POINT MUTATIONS

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  1. POINT MUTATIONS Not like X-Men

  2. MUTATION • Any change in the genetic sequence (DNA) that affects the genetic information

  3. POINT MUTATIONS • Occurs at 1 single point in DNA • These could cause one amino acid to change, which would change the protein that is being produced.

  4. POINT MUTATIONS • BASE SUBSTITUTION: • A nucleotide is replaced with a different nucleotide. • Three examples: • Transversion mutation • Transition mutation • Silent mutation

  5. BASE SUBSTITUTIONExamples: • Transversion – happens when one purine (A,G) is swapped with a pyrimidine (C,T). DNA: CTT to CAT mRNA: GAA to GUA AA: Glu to Val

  6. Transversion Substitution

  7. BASE SUBSTITUTIONExamples: • transition mutations – happen when one purine is swapped with the other purine or a pyrimidine is swapped with a pyrimidine. DNA: CTT to CCT mRNA: GAA to GGA AA: Glu to Gly

  8. BASE SUBSTITUTIONExamples: • Silent mutations – happen when a base codon is changed but both code for the same amino acid. DNA: GAA to GAC mRNA: CUU to CUG AA: Leu to Leu

  9. POINT MUTATIONS FRAMESHIFT: Because of a point mutation, there is a shift in the “reading frame” of genetic message Almost always affect all the amino acids after the mutation, which will affect the entire protein.

  10. Frameshift Mutation Examples: • Insertion • Shifts the reading to the right • DNA: from GCATCG to GCC ATC • mRNA: from CGU AGC to CGGUAG • Amino Acid: from Arg Ser to Arg STOP

  11. Point Mutation • Deletion • Shifts the reading to the left • DNA: from GCATCG to GAT CG • mRNA: from CGU AGC to CUAGC • Amino Acid: from Arg Ser to Leu

  12. A New Subtype of Brachydactyly Type B Caused by Point Mutations in the Bone Morphogenetic Protein Antagonist NOGGIN

  13. Hutchinson-Gilford progeria syndromeThe disease is caused by a small point mutation on a single gene known as LMNA. Almost all cases are caused by the substitution of only one base pair out of the approximate 25 000 DNA base pairs that compose the LMNA gene. This gene codes for the protein lamin A, which is important to determine the shape of a cell’s nucleus. It is vital in providing support to the nucleus’ inner membrane. The mutation in the LMNA gene causes an abnormal form of the lamin A protein. That malformed protein makes the inner cell membrane unstable and little by little damages the nucleus; this makes cells more prone to die prematurely. Researchers are still trying to figure out how exactly this leads to the phenotypes associated with progeria.

  14. CHROMOSOMAL MUTATIONS

  15. INVERSION and TRANSLOCATION • Inversion: 2 sections of the chromosome are reversed • Translocation: 1 part of a chromosome breaks off and attaches to another part of a chromosome • Duplication: Part of chromosome is copied

  16. Examples • ORIGINAL CHROMOSOME: • ABCDEFG – where the letters are representing geneson the chromosome. • Inversion – ABGFEDC • Translocation – ABCDXYZ • Duplication –ABBBCDEFG

  17. Inversion Brenden Adams abnormal growth rate is due to an inversion in chromosome-12, a growth gene defect that skyrocketed his growth rate. In Brenden’s case, his 12th chromosomes don’t match. Experts don’t know why, but the middle of one of them broke off, flipped around and re-attached at the zygote stage of development, disrupting a critical gene that controls growth. http://www.kimatv.com/news/local/11161021.html?tab=video

  18. Translocation Examples • Acute Promyelocytic Leukemia – caused by a rearrangement of genetic material between chromosome 9 and 22.

  19. Translocation Examples • The section on 15 is responsible for suppressing tumors (control growth). The section on 17 is responsible for helping white blood cells mature. When the two are translocated, tumors can grow and white blood cells cannot mature. It is aquired not inherited.

  20. Translocation

  21. Translocation A chromosome 5;12 translocation causes severe skeletal and composite cardiac malformations.

  22. Duplication

  23. Deletion • a portion of one chromosome is lost during cell division. That chromosome is now missing certain genes. When this chromosome is passed on to offspring the result is usually lethal due to missing genes.

  24. http://www.chemistryexplained.com/Ma-Na/Mutation.html http://embryology.med.unsw.edu.au/Defect/page21.htm http://www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html http://www.docstoc.com/docs/38810096/Mutations

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