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Mutations

Mutations. When something goes wrong…. Causes of Mutations. Causes of Mutations. Mutations are caused by changes in the nucleotide sequence of DNA or of a gene This can occur: During DNA replication During cell division After cell division. Mutations Types. Mutations Types.

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Mutations

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  1. Mutations When something goes wrong…

  2. Causes of Mutations

  3. Causes of Mutations • Mutations are caused by changes in the nucleotide sequence of DNA or of a gene • This can occur: • During DNA replication • During cell division • After cell division

  4. Mutations Types

  5. Mutations Types • Germ-Cell Mutations • Occur in an organism’s gametes • Do not affect the organism itself but may be passed to offspring • Somatic-Cell Mutations • Take place in an organisms body cells and can affect the organism • Cannot be inherited • Lethal Mutations • Cause death, often before birth

  6. Gene Mutation

  7. Gene Mutations • Point mutations affect a single nucleotide • Base pair substitution • Silent mutation • Does not change the amino acid • Missence mutation • Change of a single amino acid • Nonsense mutation • Changes amino acid to stop codon • Neutral mutation • Changes amino acid to chemical similar amino acid

  8. Gene Mutations • Frameshift Mutation • Change in reading frame due to adding or deleting a nucleotide

  9. Gene Mutations TAC GTG ATA CCA AAG TAG ACT AUG CAC UAU GGU UUC AUC UGA Met His Tyr Gly Phe Ile Stop No Mutation TAC GTG ATT CCA AAG TAG ACT AUG CAC UAA GGU UUC AUC UGA Met His Stop Nonsense Mutation TAC GTG ATA CGA AAG TAG ACT AUG CAC UAU GCU UUC AUC UGA Met His Tyr Ala Phe Ile Stop Neutral Mutation

  10. Gene Mutations TAC GTG ATA CCA AAG TAG ACT AUG CAC UAU GGU UUC AUC UGA Met His Tyr Gly Phe Ile Stop No Mutation TAC GTG ATA CCG AAG TAG ACT AUG CAC UAU GGC UUC AUC UGA Met His Tyr Gly Phe Ile Stop Silent Mutation TAC GTG ATA GCA AAG TAG ACT AUG CAC UAU CGU UUC AUC UGA Met His Tyr Arg Phe Ile Stop Missence Mutation

  11. Karyotype - Detecting Mutations! chromosomal mutations

  12. Chromosomal Mutations • These mutations can be detected by Karyotyping. • Nondisjunction • Homologous chromosomes or chromatids don’t split in division • Deletion • Loss of a piece of chromosome due to breakage • Duplication • Portion of the chromosome can be duplicated • Inversion • Part breaks off, then reattaches in reverse position • Translocation • Part breaks off, reattaches to a non-homologous chromosomes

  13. Effects of Mutations

  14. Effects of Mutations • Always result in changes to genotype but not always phenotype • Neutral • No effect • Beneficial • Enhances fitness • Deleterious • Decreases fitness

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