1 / 14

Mutations

Mutations. Genetic mistakes that can be “silent” , deadly, or beneficial. Specifically, a MUTATION can include …. Any change in the nucleotide sequence of DNA Just a single nucleotide base OR Large regions of a chromosome

saragonzalez
Download Presentation

Mutations

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. Mutations Genetic mistakes that can be “silent” , deadly, or beneficial

  2. Specifically, a MUTATION can include ….. • Any change in the nucleotidesequenceof DNA • Just a single nucleotide base OR • Large regions of a chromosome • Occasionally, mutation leads to an “improved” protein with selective advantage (drives evolution) • More often, however, they are harmful

  3. “Point Mutation” Change in one nucleotide Base Most gene mutations involve only one nucleotide, called “point mutations” • There are three types of Point Mutation (within a gene sequence): • Substitution(base switch) • Insertion (Addition of extra base) • Deletion (Removal of a base)

  4. Substitution: “The Switch” • One nucleotide is switched for another, often changing the resulting A.A. and the protein. • Sickle-cell Disease A to U Glutamine to Valine

  5. Other Point Mutations: Insertions / Deletions • When a point mutation involves the insertion of an extra, or deletionof an existing nucleotide, the “code” is shifted; this is called a “Frame Shift Mutation.”

  6. Frame shifts are Serious • An addition or deletionof a base in the DNA sequence, in turn, changes the mRNA base sequence (codons) • “Translation” of every condon and corresponding amino acid “downstream” from the added base is changed • This often results in either a defective, nonfunctional, or different protein • Lactose Intolerance= no lactase made

  7. Frame shift changes more than one amino acid

  8. Substitution, Insertion, and Deletion FRAME SHIFTS Deletion Substitution Insertion FRAMESHIFT MUTATION = LACTOSE INTOLERANCE Go to Section:

  9. Chromosomal Mutations • Chromosomal mutations involve changes in thestructureornumberof chromosomes. Changes may include: • Location of genes • Number of copiesof genes

  10. Types of Chromosomal Mutations • Inversion– the order of genes on a chromosome are inverted • Translocation – the movement of a chromosome fragment to a nonhomologous chromosome • Deletion– loss of large regions of a chromosome • Duplication– duplication of a large region of chromosome

  11. Chromosomal Mutations Deletion B gene deleted B gene duplicated Duplication B + E gene flip positions Inversion Genes exchanged between two different chromosomes Translocation

  12. Fate of a Mutation depends on where its happening • If a mutation occurs in the DNA (genes) located in body cells (somatic), then only cells arising from these cells will contain the mutation. • If a mutation occurs in the DNA (genes) of sex cells (gametes), then the mutation may be passed onto offspring

  13. Typical Gene Structure Promoter(RNA polymerase binding site) Regulatory sites DNA strand Start transcription Stop transcription

  14. Not all genes are “turned on” • Remember all cells of an organism are genetically identical (their DNA is exactly the same) • Only genes that are “turned on” will be used or expressed • Different cell types (with different jobs) turn on and use different genes

More Related