Mutations Flashcards
Result in partially or fully non functional gene product
-known as a null mutation
Loss of function mutation
Causes the gene product to have more activity
ex. cancer cells
Gain of function mutiation
Drives evolution through adaptation, not always bad
Mutation
Is the creation of mutations
Mutagenesis
Mistakes during replication
Base can exist in 2 isomers with different base pairing properties
ex. G=A
Spontaneous Mutations
Caused by mutagens:
- chemcals
- environmental factors that cause mutation
- Change covalent bonds
Induced mutations
Mutagens:
- Base modifying agents
- intercalating agents
- base analogs
Insert themselves between base pairs
Intercalating agents
Look like DNA and nucleotides, so they get translated
Base analogs
Two major classes of mutations
- Somatic Mutation
2. Germ-line Mutation
Mutation not passed on to next generation
ex. moles
Somatic Mutation
Transmitted to future generations
-progeny has the mutation in both somatic and germ-line cells.
Germ-line Mutation
Which of the following categories of mutation is not possible to pass to offspring?
a. silent
b. somatic
c. frameshift
d. induced
e. x-linked
b. somatic
Types of mutations
- Base-pair substitutions
2. Base pair insertions/deletions
Mutation that changes 1 basepair to another basepair
Base pair substitution
Intercalating; Mutation that adds or removes a basepair
Base pair insertion/deletion
2 Major types of base pair substitutions
- Transition mutation
2. Transversion mutation
Mutation that changes one purine-pyrimidine basepair to another purine-pyrimidine basepair.
Transition Mutation
Mutation that changes one purine-pyrimidine basepair to a pyrimidine-purine basepair or vice versa.
Transversion mutation
A change in a codon so that a different amino acid is added to the polypeptide
-phenotypic change depends on severity of mutation
Missense Mutation
Change in structure=change in function
phenotypic result
Change from a codon that indicates an amino acid to a stop codon.
Nonsense Mutation
Changing 1 codon for 1 amino acid to another codon for the same amino acid
Silent Mutation
Change from an amino acid to another amino acid with similar chemical properties
-type of transition mutation
Neutral Mutation
- A insertion/deletion has changed the frame
- Shift in the reading frame so that missense or stop results
Frameshift Mutation
- Area of genome has 3 nucleotides repeated many times in a row.
- If happens in a coding region, long stretches of the same amino acid repeats itself
- Problem: sticks to each other and cannot do anything.
Trinucleotide Repeat Expansion
Change wild type allele to mutant allele
Forward Mutation
Change to premutation state
-changes mutant allele so that phenotype becomes more like wild type
Reverse Mutation
A mutation that masks original phenotype
-mutation at a different site than the original mutation
Suppressor mutations
Within the same gene
-If an insertion occurs, a deletion farther down will rest the frameshift.
Intra genic suppressors
Mutation in another gene
Inter genic suppresors
