Genetic Mutations


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What are some genetic mutations and what is their affect?

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Genetic Mutations

  1. 1. Genetic Mutations
  2. 2. <ul><li>What is a mutation? </li></ul><ul><li>What are some examples of harmful mutations? </li></ul><ul><li>Neutral Mutations are… </li></ul><ul><li>What are some examples of beneficial mutations? </li></ul>At the End of Today, You Should Know:
  3. 3. What is a Mutation? <ul><li>Abrupt, heritable changes in a single gene or a region of a chromosome, can also include alterations in chromosome number </li></ul><ul><li>Mutations are the fuel for evolution and are the basis for the variation in population. </li></ul>
  4. 4. What is a Mutation? <ul><li>Can be when one letter is switched - accidentally copied incorrectly within the DNA. </li></ul><ul><li>When one section of the DNA, sometimes an entire gene, is not properly connected to the rest of the DNA; sometimes it even reconnects to another chromosome </li></ul><ul><li>One section of DNA, sometimes an entire gene, appears more than once </li></ul>
  5. 5. What is a Mutation? <ul><li>More or less chromosomes than 46 </li></ul><ul><li>Will only get passed on to offspring when the sex cells contain the mutation </li></ul><ul><li>Can be caused after birth by environmental factors like radiation and chemicals, which can alter a person’s DNA, even in their sex cells, causing their offspring to have disorders </li></ul>
  6. 6. Some Mutations Cause Disorders…
  7. 7. Down’s Syndrome <ul><li>• Offspring receives 3 copies of 21 st chromosome </li></ul><ul><li>90% of the time the extra chromosome comes from the mother </li></ul><ul><li>Affects 1 in 800 live births </li></ul>
  8. 8. Effects of Down’s Syndrome <ul><li>Different in each person </li></ul><ul><li>Does not usually pass this onto children </li></ul><ul><li>Common effects include </li></ul><ul><ul><li>Learning Disabilities </li></ul></ul><ul><ul><li>Heart defects (can usually be corrected with modern technology) </li></ul></ul>
  9. 11. Turner’s Syndrome <ul><li>45 (instead of 46) chromosomes </li></ul><ul><li>offspring are born with one X chromosome (no Y; only one X) </li></ul><ul><li>only affects women </li></ul><ul><li>In about 80% of cases the X comes from the mother and the father’s sperm has no Y </li></ul><ul><li>Affects 1 in 2500 live births </li></ul>
  10. 12. Effects of Turner’s Syndrome <ul><li>• Sometimes a lack of ovarian development </li></ul><ul><li>• Can have more masculine qualities (stronger), although are female </li></ul><ul><li>In some cases: </li></ul><ul><ul><li>Webbed neck </li></ul></ul><ul><ul><li>Arms that turn in at the elbow </li></ul></ul><ul><ul><li>Low hairline on the back of the head </li></ul></ul>
  11. 15. Klinefelter’s Syndrome <ul><li>• Offspring inherit a Y chromosome and two X chromosomes </li></ul><ul><li>Because there is a Y all offspring are male </li></ul><ul><li>Sometimes the extra X comes from the egg and sometimes it comes from the sperm </li></ul><ul><li>Occurs in 1 out of every 500 – 1000 live births </li></ul>
  12. 16. Effects of Klinefelter Syndrome <ul><li>Sparse facial and body hair </li></ul><ul><li>Underdeveloped muscles </li></ul><ul><li>Wide hips </li></ul><ul><li>Tall height </li></ul><ul><li>Long legs & arms </li></ul><ul><li>Higher-pitched voice </li></ul>
  13. 18. Albinism <ul><li>Caused by a recessive gene </li></ul><ul><li>Causes genes to release unusual amounts of melanin (chemical that provides color) </li></ul><ul><li>Affects 1 in 17,000 people </li></ul><ul><li>People of all races are susceptible </li></ul><ul><li>All animals are susceptible </li></ul>
  14. 19. Effects of Albinism <ul><li>Light skin </li></ul><ul><li>Light hair </li></ul><ul><li>Reddish or violet eyes (in some albinos) </li></ul><ul><li>Lack of eye pigment leads to vision problems </li></ul><ul><li>Skin cancer – especially in third world countries </li></ul>
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  20. 28. There are MANY other mutations…
  21. 29. Not all Mutations Are Bad…
  22. 30. Mutations Can Be Neutral <ul><li>They may have little or no effect on the survival of an organism or on its ability to reproduce. </li></ul><ul><li>They may result in the same kind of organism - meaning that the change still tells the cell to do what it should, so there is no difference. </li></ul><ul><li>It is estimated that the average human has 50-100 mutations within their DNA - most (if not all) are neutral or beneficial </li></ul>
  23. 31. Mutations Can Be Beneficial <ul><li>Bacterial resistance to antibiotics </li></ul><ul><li>Insecticide resistance in bugs </li></ul><ul><li>Rapid mutation rates in virus’s proteins allowing them to adapt to new “hosts” </li></ul>
  24. 32. Mutations Can Be Beneficial <ul><li>In humans, it can be a different set of circumstances… Here’s an example: </li></ul><ul><li>Sickle-Cell Anemia is a genetic disorder in which there is a defect in the structure of red blood cells. This leads to fatigue and anemia when not treated. </li></ul><ul><li>However, it has been found that people who are carriers for Sickle-Cell Anemia also has some genetic protection against another disease, malaria. </li></ul>
  25. 33. Mutations Can Be Beneficial <ul><li>• In evolutionary studies, scientists have connected the presence of a brain chemical microcephalin (a proposed mutation) with the human’s development of art, music, and complex tool-making practices </li></ul><ul><li>This same research indicates that the human brain is still evolving and becoming more and more capable of more complex tasks </li></ul><ul><li>Some humans have been found to have mutations that protect them from other diseases, such as AIDS </li></ul>