1 / 35

CHANGES IN THE GENETIC CODE

CHANGES IN THE GENETIC CODE. Ectrodactyly. What do they all have in common? They’re all mutations!. MUTATIONS. a change in the DNA code causes a different (sometimes wrong) type of protein to be made may or may not be good for the organism. ALONG THE WAY. good changes occur

oprah
Download Presentation

CHANGES IN THE GENETIC CODE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHANGES IN THE GENETIC CODE

  2. Ectrodactyly

  3. What do they all have in common? • They’re all mutations!

  4. MUTATIONS • a change in the DNA code • causes a different (sometimes wrong) type of protein to be made • may or may not be good for the organism

  5. ALONG THE WAY • good changes occur • bad changes occur • changes that don’t matter either way

  6. CHANGE IS NECESSARY • without changes we would all look alike • without changes we would not evolve • without changes we would not develop immunities to disease • SO… Is change/variation a good thing??? • YES!

  7. Causes of Variation • Crossing Over • Mutations • Some happen randomly • Some caused by Mutagens (agents that cause mutations) • Nuclear Radiation • Ultraviolet Light • X Rays • http://learn.genetics.utah.edu/units/disorders/sloozeworm/mutationbg.cfm

  8. CROSSING OVER • occurs when homologous chromosomes trade segments • occurs during Prophase I of Meiosis

  9. entire gene is switched • involves the variation of a single trait • gene for big ears exchanges with gene for small ears

  10. Advantages • variation of offspring from parents • allows for “good” changes • Better chance of passing on genes for survival

  11. 3 TYPES OF MUTATIONS • Chromosomal mutations • Gene mutations • Somatic mutations • these usually occur during mitosis and involve a chromosomal mutation • involved with body cells, not sex cells • tumors are the result

  12. Research your mutation • 1. Answer these questions • What does the name of the mutation mean? • What happens to the chromosome? • What is an example?

  13. CHROMOSOMAL MUTATIONS • NONDISJUNCTION • DELETION • INVERSION • DUPLICATION • TRANSLOCATION • INSERTION

  14. NONDISJUNCTION • failure of homologous pairs to separate during meiosis • correct number of chromosomes are not present in the gamete • after fertilization, diploid number is not restored

  15. Examples • Trisomy 21(Down Syndrome)- 3 copies of chromosome 21 • Klinefelters Syndrome- XXY • Turner Syndrome- X • “Supermales” - XYY

  16. DELETION A SEGMENT OF A CHROMOSOME IS DELETED

  17. Examples • Cri-du-chat syndrome- “cry of the cat”- deletion of piece of chromosome #5 • Angelman Syndrome- deletion of piece of chromosome #15 • Prader-Willi Syndrome- deletion of piece of chromosome #15

  18. INVERSION A SEGMENT OF THE CHROMOSOME IS FLIPPED IN THE OPPOSITE DIRECTION

  19. DUPLICATION A SEGMENT OF THE CHROMOSOME IS COPIED TWICE

  20. TRANSLOCATION SEGMENTS FROM TWO DIFFERENT CHROMOSOMES ARE SWITCHED

  21. Example • Translocation Down Syndrome • Instead of being 3 separate copies of chromosome 21, the extra copy is actually attached to another chromosome

  22. INSERTION A SEGMENT OF ONE CHROMOSOME IS INSERTED INTO A DIFFERENT CHROMOSOME

  23. GENE MUTATIONS • POINT MUTATIONS • FRAME SHIFT • insertions • deletions • INVERSIONS

  24. LETS MUTATE! • Start with an original strand of DNA GCC TTA CGT TTA CGA CTG TAC GTA CGG AATGCAAATGCT GAC ATG CAT A B C D • lets assume this strand codes for a protein AMINO ACIDS

  25. POINT MUTATIONS TTA CGT TTA CGA AAT GCA AAT GCT ORIGINAL 1 base is replaced with another base TTA CTT TTA CGA AAT GAA AAT GCT MUTATION B E

  26. Example • Sickle Cell Anemia- changing 1 base causes mutation that codes for valine instead of glutamate in the protein hemoglobin • Individuals produce different type of hemoglobin • Red Blood Cells become sickle shaped and don’t pass thru blood vessels as easily • Cells die sooner than normal • Individuals don’t get as much oxygen

  27. http://www.montgomerycollege.edu/~wolexik/Sickle%20Cell%20Anemia%20400x.jpghttp://www.montgomerycollege.edu/~wolexik/Sickle%20Cell%20Anemia%20400x.jpg

  28. FRAME SHIFTS TTA CGT TTA CGA AATGCAAATGCT ORIGINAL A B C D TTA CGT TTA ACG A AATGCAAATTGC T INSERTION-base is inserted A B C F TTA CGT TAC GA AATGCAATG CT DELETION- base is deleted A B G

  29. INVERSIONS TTA CGT TTA CGA AATGCAAATGCT ORIGINAL A B C D Codon is found in reverse order TTA TGC TTA CGA AATACGAATGCT INVERSION A H C D

  30. Consequences • Sometimes mutations are bad and cause for different proteins to be made • But- if you look at the amino acid chart- several different codons code for the same amino acids • Mutations can occur but wouldn’t be noticed • Some mutations are masked by other genes

More Related