Mutations and regulation
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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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Making mistakes
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
1. GENE Mutations

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

Examples of point mutations
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!

Sustitution can still be bad
Sustitution can still be bad:

  • Sickle cell anemia

Other point mutations
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!!!

Frameshift mutation insertions deletions
Frameshift Mutation(insertions & deletions)

  • Frameshift mutations – adding or deleting a nucleotide causing a shift of codons.



  • Or



It s like this frameshifting
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!!!

Chromosomal mutations
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

c) Inversions – reverse the direction of some of the chromosome

d) Translocations – part breaks off and attached to another chromosome

3 polyploidy
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)



  • 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.

Gene regulation
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.

Iii differentiation
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!!!