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DNA - MUtations

DNA - MUtations. GENE Mutations. CHROMOSOMAL Mutations. DNA - Mutations. A third key function/ability of DNA is that it can undergo a mutation. Most of the time these mutations are negative, but on occasion a newer better form of a gene may be produced.

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DNA - MUtations

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  1. DNA - MUtations GENE Mutations CHROMOSOMAL Mutations

  2. DNA - Mutations A third key function/ability of DNA is that it can undergo a mutation. Most of the time these mutations are negative, but on occasion a newer better form of a gene may be produced.

  3. The two major categories of Mutations are: • Gene Mutations • Chromosomal Mutations Chromosomal mutations affect a chunk of a chromosome and therefore may affect hundreds of genes. Ex. Chrom #1 has over 4,000 genes Gene mutations affect one gene.

  4. Let’s start by looking at Chromosomal Mutations. Most Chromosomal mutations occur when Homologous chromosomes line up with each other and a piece of one chromosome breaks off and switches places with the complimentary piece on its partner chromosome.

  5. This process is calledCrossoverand its purpose is to create more variation in the chromosomes that can be passed onto offspring in the sex cells – Eggs and Sperm

  6. Crossover

  7. DELETION Sometimes during crossover, a piece of chromosome breaks off and moves over to the other chromosome, but the piece that is supposed to come in and replace it does not do so.

  8. Example: William’s Syndrome Chromosome #7

  9. DUPLICATION Sometimes during crossover, a piece of chromosome from the homologous (partner) chromosome comes in and joins on, but the piece that it was supposed to replace, never left.

  10. Example: “Inv Dup 15” Syndrome Seizures, scoliosis and mental retardation

  11. INVERSION Sometimes during crossover, the proper piece will come in but it will insert itself backwards (inverted) into the existing chromosome. Even though all the genes (d,e, and f) are replaced, they cannot be properly read, because they are being read backwards.

  12. TRANSLOCATION In the final type of chromosomal mutation, two chromosomes line up and undergo crossover, but they are not homologous. So for example instead of chromosome #5 matching up with another #5, it lines up and exchanges sections with chromosome #18. That is really bad!

  13. Affects the liver, heart kidney, and other systems of the body. Problems associated with the disorder generally become evident in infancy or early childhood. Example: “Alagille Syndrome”

  14. summary

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