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Mutations and Regulation

Mutations and Regulation. Making Mistakes. Mutations = changes in the genetic material (mistakes) Several types: Gene mutations = mutation to a single gene Chromosomal mutations = mutations to the whole chromosome. 1. GENE Mutations.

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Mutations and Regulation

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  1. Mutations and Regulation

  2. Making Mistakes • Mutations = changes in the genetic material (mistakes) Several types: • Gene mutations = mutation to a single gene • Chromosomal mutations = mutations to the whole chromosome

  3. 1. GENE Mutations • Point mutations – involve changes to one or a few nucleotides; affect a single point in the DNA sequence

  4. Examples of Point Mutations a) Substitutions - one nucleotide is substituted for another • Ex: AGGUC changed to ACGUC • The dog bit the cat changed to… • The dog bit the car. • Affects one amino acid – less damage!

  5. Sustitution can still be bad: • Sickle cell anemia

  6. Other Point Mutations: b) Insertion: one nucleotide added • …AAUCGC… becomes …ACAUCGC… c) Deletion: one nucleotide deleted • …AAUCGC… becomes …AAU-GC… • THESE can be very bad!!!

  7. Frameshift Mutation(insertions & deletions) • Frameshift mutations – adding or deleting a nucleotide causing a shift of codons. • AUG GCC UAC CGA… • AUUGGC CUA CCG A… • Or • AUG GCC UAC CGA • AGGCCU ACC GA…

  8. It’s like this…frameshifting. • The cat ate the fat rat. • Tec ata tet hef atr at… • Or • The dog ran and bit the cow. • The edo gra nan dbi tth eco w. • These can totally ruin a whole gene!!!

  9. Chromosomal Mutations • Involve changes in the number or structure of the entire chromosome. • There are: • Deletions– loss of part of the chromosome b) Duplications – extra copies of part of the chromosome is made

  10. c) Inversions – reverse the direction of some of the chromosome d) Translocations – part breaks off and attached to another chromosome

  11. 3) Polyploidy: • an organisms has extrasets of chromosomes • Lethal or harmful to animals • Ex: Most die as embryos or fetuses; defects in nearly all organs. • Plants that are polyploids are often larger and stronger!! (bananas, other fruits) YUM! YUM!

  12. Plants Polyploidy

  13. Luckily… • Most mutations are neutral – have little or no affect on the organism • Others are harmful (disorders, cancer, etc.) • But, they are the source of genetic variability though!! Help things adapt.

  14. Gene Regulation 1. DNA and RNA polymerase and other enzymes also “proof-read” the DNA and RNA to fix mutations if possible. 2. Repressors are proteins that bind to specific genes on chromosomes stopping transcription of a gene until the gene is needed. 3. Other types of proteins can speed up transcription if necessary.

  15. III. Differentiation • A life starts with ONE cell. • They have to “know” to specialize (differentiate) • Hox genes control differentiation – they are the master control gene! • If mutated, problems arise – you can grow legs instead of antennae on fruit flies!! • The control genes are similar in all animals – they took an eye gene and put it in the leg gene of a fruit fly and grew an eye on the fruit fly’s leg! • This is where stem cell research comes in!!!

  16. Other mutations:

  17. Hands and Feet

  18. 5 legs on a lamb

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