Biology 3594A Study Guide - Final Guide: Pyrimidine, Purine, Mutagen
Lecture 5 Flashcards
Front (Term)
Back (Definition)
2 origins of gene mutation
- Name
- Frequency
- possible causes
1. Endogenous (spontaneous)
- frequency is 10^-5 to 10^-8
- possible causes: cell metabolism, DNA chemistry
- usually a deletion
2. Exogenous (induced)
- frequency is dose dependent
- possible causes: mutagen exposure, environmental exposure
Spontaneous mutation
Arose without intervention of scientific investigator or
movement of the animal into an environment with the intent
to cause a change
3 categories of gene mutation
1. A change in one nucleotide
2. a change in copy number
3. Insertion of a mobile element
Change in one nucleotide (3)
- Substitution
- Deletion (more frequent than insertions for spontaneous
mutation)
- Insertion (usually increasing stutter, inserting what you've
seen before, creating a run)
Change in copy number (2)
Strings of sequence, tend to have a unit
- repeat expansion
- repeat contraction
Insertion of a mobile element (2)
- transposons (cut paste, deletion at one site and insertion at
another)
- retrotransposons (copy paste)
Tend to be viral
Larger units than copy number change
Gene mutation: 2 consequences and
their frequency
1. Loss of function (most frequent)
2. Gain of function (rare)
2 Types of loss of function
- Hypomorphic: reduced function
- Amorphic: eliminated function
2 Types of gain of function
Hypermorphic: enhanced function
Neomorphic: alternate function
Transitions
- Purine to purine or pyrimidine to pyrimidine
A to G or G to A
C to T or T to C
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Document Summary
Arose without intervention of scientific investigator or movement of the animal into an environment with the intent to cause a change: a change in one nucleotide, a change in copy number, insertion of a mobile element. Deletion (more frequent than insertions for spontaneous mutation) Insertion (usually increasing stutter, inserting what you"ve seen before, creating a run) Strings of sequence, tend to have a unit. Transposons (cut paste, deletion at one site and insertion at another) Gene mutation: 2 consequences and their frequency: loss of function (most frequent, gain of function (rare) Purine to purine or pyrimidine to pyrimidine. No change in amino acid or phenotype aka synonymous substitution. *unless hypomorphic phenotype related to trna abundance trnas have different biases in abundance. If the mutation messes up a trna for an anticodon that is limiting, could end up with a hypomorphic phenotype (difference in protein abundance) Aka nonsynonymous mutation: conservative (similar amino acid)