M3: Gene & Chromosomal Mutations Flashcards
Alteration in the DNA sequence
Any base-pair change in the DNA MOLECULE
Gene Mutation
Basis of Classifying Gene Mutation
- Cause
- Location
- Molecular Change
- Phenotypic Effects
Types of Mutations Based on Cause
- Spontaneous
- Induced
Based on Cause
Results from the occasional errors during DNA Replication
*Very low mutation rate
*Occurs without external intervention
Spontaneous
Based on Cause
Using Mutagens (Biological-Transposons, Chemical-Base analogs, & Physical-UV Radiation)
*Induced by humans
*High mutation rate
Induced
Types of Mutations Based on Location
- Somatic
- Germ Line
- Autosomal
- Sex Chromosome
- Coding Regions
- Non-coding Regions
Based on Location
May result to altered cellular functions of the tumor
*Not heritable
*Ex: Non-reproductive Cells
Somatic Mutation
Based on Location
Heritable
Ex: Reproductive Cells
Germ Line Mutation
Based on Location
Mutations within genes located on the chromosomes not related to sex
Autosomal Mutation
Based on Location
Ex:
* X-linked mutation
* Y-linked mutation
Sex Chromosome Mutation
Based on Location
Regulatory sequences
Ex: Introns
Non-coding region of the gene
Based on Location
Ex: Exons
Coding Region of the Gene
How can DNA mutation can be fixed?
DNA Repair Mechanism
Existence of Gene Mutation
Permanent
Based on Cause
A possible source of spontaneous gene mutation
DNA Polymerase
Based on Location
An example of non-coding region for mutation
Cis-Acting Elements
Types of Mutation based on Molecular Change
- Frameshift
- Rearrangement
- Base Substitution
Based on Molecular Change
Point Mutation
Replacement of one base by another base
Base Substitution
Purine to Purine Substitution
Transition
Purine to Pyrimidine Substitution
Transversion
Effects of Base Substitution
- Silent Mutation
- Non-sense Mutation
- Missense Mutation
Base substitution effects
No effect on the resulting protein
Silent Mutation
Base Substition Effect
Results to a stop codon
Nonsense mutation
Base Substitution Effect
Results to a faulty protein
Missense Mutation
Addition or deletion of nucleotides
* Most prevalent at repeated sequence
* No effect if adds/deletes units
Frameshift
Types of Framshift
- Reading frame, +1
- Reading frame, -1
Deletion or Addition of large number of nucleotides
Rearrangement
Types of Rearrangement
- Large segment inserted
- Large segment deleted
Rearrangement Effect
Truncated protein
Large segment deleted