Genetic Mutations 1


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Genetic Mutations 1

  1. 1. Genetic Mutations Mutation: any mistake, or change, in DNA sequence
  2. 2. Types of mutations: • Point Mutations • Frameshift Mutations • Chromosomal Mutations
  3. 3. Point Mutations • Changes in a single base pair in DNA • Errors caused by point mutations don’t usually interfere much with protein function; however, they CAN be disastrous. Example: Normal: THE DOG BIT THE CAT Mutated: THE DOG BIT THE CAR
  4. 4. Example Normal AUG UUU GGC GCA UUG UAA Met Phe Gly Ala Leu Stop Mutated AUG UUU AGC GCA UUG UAA Met Phe Ser Ala Leu Stop
  5. 5. Frameshift Mutations • Mutations in which a single base is added or deleted from DNA • Adding/deleting one base changes every amino acid in the protein after. • Proteins produced seldom function properly
  6. 6. Example Normal AUG UUU GGC GCA UUG UAA Met Phe Gly Ala Leu Stop Mutated AUG UUG GCG CAU UGA AA Met Leu Ala His Cys
  7. 7. Chromosomal Mutations Types: 1. Deletions: part of chromosome is left out 2. Insertions: part of a chromosome is broken off and attaches to the sister chromatid 3. Inversions: part of a chromosome breaks out and is reinserted backwards 4. Translocations: part of one chromosome breaks off and adds to a different chromosome
  8. 8. Chromosomal Mutations (con’t) • Nondisjunction: chromosomes fail to separate properly during meiosis – Trisomy: extra chromosome • Down Syndrome – Triploidy: 3 sets of chromosomes • Banana plants – Monosomy: lack a chromosome
  9. 9. Causes of Genetic Mutations Spontaneous Mutations Mutations that occur randomly for no reason… Environmental Causes Environmental agents X-rays UV light Radiation Certain chemicals
  10. 10. Genetic Disorders
  11. 11. Cystic Fibrosis • Caused by recessive genes on pair 7 • Causes thick mucus to form in the respiratory and GI tracts • Mucus clogs lungs • Drugs administered to relieve symptoms • Exclusively among Caucasians
  12. 12. Osteogenesis imperfecta • “Imperfect Bone Formation” • Brittle bones • Samuel L. Jackson portrayed a character suffering from this in Unbreakable
  13. 13. Multiple Neurofibromastosis • Inherited • “Elephant Man Disease” • Multiple benign tumors that form in skin (disfiguring)
  14. 14. Klinefelter Syndrome • Nondisjunction of sex chromosomes • Males have XXY sex chromosomes • Causes long legs, enlarged breasts, low intelligence, small testes, sterility, and chronic pulmonary disease
  15. 15. Twin-to-Twin Transfusion Syndrome • A placental abnormality, which causes disproportionate blood, transfers between twins. • One twin receives too much blood and the other does not receive enough
  16. 16. Fragile X Syndrome • Turns off a gene that develops nerve connections to the brain • Causes mental retardation and autistic-like behaviors • No cure
  17. 17. Tay-Sachs Disease • Disorder of the central nervous system • Child develops symptoms after birth: diminished brain function and seizures • Children die by the age of 5