UNIT 6: Mutations Flashcards
Mutation/Polymorphism:
<1% of population
Mutation
Mutation/Polymorphism:
Carrier
Mutation
Mutation/Polymorphism:
Diseased
Mutation
Mutation/Polymorphism:
> 1% of population
Polymorphism
Mutation/Polymorphism:
Not affected
Polymorphism
Mutation/Polymorphism:
> 90% Single Nucleotide Polymorphism (SNP)
Polymorphism
Genetic polymorphism has at least __ alternate DNA sequences
2
T/F: Genetic polymorphism is generally not associated with disease
T
Genetic polymorphism may not be associated with disease, but may result to:
Result in ___
Phenotype
Genetic polymorphism may not be associated with disease, but may result to:
Be a risk of ___
Disease
Genetic polymorphism may not be associated with disease, but may result to:
___ the function or expression level of a protein
Alter
A ___ is any heritable change in the amount or structure of genetic material
Genetic mutation
Classification of mutations can be based on:
Origin
Cell type
Expression
Effect on function
Molecular change and its effects on protein products
Mutation/Polymorphism:
Population attribute
Polymorphism
Mutation/Polymorphism:
Presence of more than one allele at a particular locus in a particular population
Polymorphism
Single base pair change in the nucleotide sequence
Single nucleotide polymorphism
Mutation/Polymorphism:
Human gender, and ABO blood group
Polymorphism
Mutation/Polymorphism:
Natural selection does not affect alleles
Polymorphism
Mutation/Polymorphism:
Physical event
Mutation
Mutation/Polymorphism:
Permanent alteration of a nucleotide sequence of a gene
Mutation
Mutation/Polymorphism:
Sickle cell anemia, hemophilia, cystic fibrosis, Klinefelter syndrome, & turner syndrome
Mutation
Mutation/Polymorphism:
Natural selection selects the mutations that are best suited for the environment
Mutation
The rate at which new mutations appear in a genome is ___ proportional to the so-called effective population size of the species
Inversely
___ have the largest populations and lowest mutation rates
Microbes
Mutation based on origin:
Occurs in absence of known mutagen
Spontaneous
Mutation based on origin:
Statistically random, unpredictable events
Spontaneous
Mutation based on origin:
Occurs in presence of known mutagen
Known
An agent that changes genetic material
Mutagen
Type of mutagen based on effect:
Congenital malformations
Teratogens
Type of mutagen based on effect:
Tumor formation, cancer-causing agents
Carcinogens
Type of mutagen based on effect:
Chromosomal abnormalities
Clastogens
Type of mutagen based on effect:
DNA damage
Non-specific
Type of mutagen based on effect:
Thalidomide
Teratogens
Type of mutagen (physical/ chemical/ biological):
Ionizing radiations
Physical
Type of mutagen (physical/ chemical/ biological):
Non-ionizing radiations
Physical
Type of mutagen (physical/ chemical/ biological):
Heat
Physical
Type of mutagen (physical/ chemical/ biological):
Alkylating agents
Chemical
Type of mutagen (physical/ chemical/ biological):
Deaminating agents
Chemical
Type of mutagen (physical/ chemical/ biological):
Intercalating agents
Chemical
Type of mutagen (physical/ chemical/ biological):
Virus
Bacteria
Transposons
Biological
Mutation based on cell type:
Occurs in nonreproductive cells
Somatic
Mutation based on cell type:
Can yield a genotypic mixture (mosaic) of normal and mutant tissue
Somatic
Mutation based on cell type:
Most common cancers
Somatic
Mutation based on cell type:
Occurs in reproductive cells
Germ line
Mutation based on cell type:
Inherited
Germ line
Mutation based on expression:
Expressed only under restrictive condition
Conditional
Mutation based on expression:
Effect of mutation can be turned on or off by experimenter
Conditional
Mutation based on expression:
Expressed under permissive conditions as well as restrictive conditions
Unconditional
Mutation based on effect on function:
Eliminates normal function
Loss of function / amorphic
Mutation based on effect on function:
Results in complete gene inactivation or in a completely nonfunctional gene product
Loss of function / amorphic
Mutation based on effect on function:
Deletion of all or part of a gene
Loss of function / amorphic
Mutation based on effect on function:
Amino acid replacement that inactivates the protein
Loss of function / amorphic
Mutation based on effect on function:
Reduces normal function, but does not eliminate, the level of expression of a gene or the activity of the gene product
Hypomorphic / leaky mutation
Mutation based on effect on function:
Individuals may have enough enzyme activity to produce a quasi-normal phenotype
Hypomorphic / leaky mutation
Mutation based on effect on function:
Increases normal function
Gain of function / hypermorphic
Mutation based on effect on function:
Produces a greater-than-normal level of gene expression
Gain of function / hypermorphic
In hypermorphic mutation, mutation changes the regulation of the gene so that the gene product is ___
overproduced
Mutation based on effect on function:
Expressed at incorrect time or in inappropriate cell types
Ectopic expression / neomorph
Mutation based on effect on function:
Qualitatively alters the action of a gene
Ectopic expression / neomorph
Mutation based on effect on function:
Mutant gene product interferes with normal gene product
Antimorphic
Recessive mutations are usually ___ of function
Loss
T/F: Dominant mutations can only be caused by a gain of function
F (can be loss or gain)
Mutation based on molecular change:
Most common type
Substitution
Mutation based on molecular change:
Replacement of a single nucleotide by another
Substitution
Replacement by the same type of nucleotide
Transition
Substitution of a pyrimidine by a purine or vice versa
Transversion
Transition/Transversion:
More likely to cause disease
Transversion
T/F: only Adenine to Guanine and Cytosine to Thymine are transitions, everything else are transversion
T
Transition/Transversion:
Substitution of purine from another purine base or pyrimidine from another pyrimidine
Transition
Transition/Transversion:
Most common type of point mutation
Transition
Transition/Transversion:
One possible
Transition
Transition/Transversion:
Less likely to cause amino acid sequences; remains as a silent mutation
Transition
Transition/Transversion:
Interchanges of bases within single ring structures or within double ring structures can be observed
Transition
Transition/Transversion:
Substitution of a purine from a pyrimidine or pyrimidine from a purine
Transversion
Transition/Transversion:
Less common
Transversion
Transition/Transversion:
More likely to cause amino acid sequence changes; has a pronounced effect on the resulting protein
Transversion
Transition/Transversion:
Interchange occurs in a single ring structure with double ring structure or double ring structure with a single ring structure
Transversion
Mutation based on molecular change:
Involves the loss of one or more nucleotides
Deletion
Mutation based on molecular change:
Involves the addition of one or more nucleotides into a gene
Insertion
Deletion pattern:
Deletion of amino acids that may affect protein function or stability
Multiple of 3 (codon)
Deletion pattern:
Likely to result to frameshift mutation
Not multiple of 3
Deletion pattern:
May arise through unequal crossover between repeat sequences
Large deletion
Deletion pattern:
Either partial gene deletion or whole gene deletion
Large deletion
Three-base deletion in the common ___ ___ allele results in synthesis of a protein that lacks amino acid 508 (phenylalanine)
Cystic fibrosis (CF)
Mutation based on molecular change:
Expansion of trinucleotide repeat
Insertion
Insertion pattern:
Amplification of a sequence of three nucleotides, which prevents normal expression of the gene
Expansion of trinucleotide repeat
Insertion patterns:
Involves dynamic mutations wherein the repeat sequence becomes more unstable as it expands in size
Expansion of trinucleotide repeat
Possible causes of expansion of trinucleotide repeat
- Unequal sister chromatid exchange on nonreplicating DNA
- Slipped-strand mispairing and polymerase slippage in replicating DNA
Identify the repeating insertion pattern:
Fragile X syndrome (FMR1 gene)
CGG
Identify the repeating insertion pattern:
Huntington disease (HTT gene)
CAG
Identify the repeating insertion pattern:
Myotonic dystrophy (DMPK gene)
CTG
Identify the repeating insertion pattern:
Friedrich ataxia (FXN1 gene)
GAA
Mutation based on effect on protein products:
Silent mutations
Synonymous mutations
Mutation based on effect on protein products:
Missense mutations
Nonsense mutations
Frameshift mutation
Nonsynonymous mutations
Mutation based on effect on protein products:
Mutation does not alter the polypeptide product of the gene
Synonymous mutations
Mutation based on effect on protein products:
Base substitution occurs but does not change the amino acid sequence
Silent mutations
Mutation based on effect on protein products:
Mutation leads to an alteration in the encoded polypeptide
Nonsynonymous mutations
Mutation based on effect on protein products:
Likely to result in abnormal function, which is usually associated with disease, or lethality
Nonsynonymous mutations
Mutation based on effect on protein products:
Base-pair substitutions that produce a change in a single amino acid
Missense mutations
Mutation based on effect on protein products:
Change in amino acid may affect the protein structure
Missense mutations
Mutation based on effect on protein products:
Sickle cell anemia: affects the beta-globin chain of hemoglobin
Missense mutations
Mutation based on effect on protein products:
Base-pair substitutions that produce a stop codon in the mRNA
Nonsense mutations
Mutation based on effect on protein products:
Result in a premature termination of the polypeptide chain
Nonsense mutations
Mutation based on effect on protein products:
Unlikely to retain normal biological activity, especially when there is a loss of an important functional domain(s) of the protein
Nonsense mutations
Mutation based on effect on protein products:
Beta-0 thalassemia: affects the beta-globin chain of hemoglobin
Nonsense mutations
Mutation based on effect on protein products:
When a mutation involves the insertion or deletion of nucleotides that are not a multiple of three
Frameshift mutation
Mutation based on effect on protein products:
Resulting amino acid sequence bears no resemblance to the normal sequence and may have an adverse effect on its function
Frameshift mutation
Mutation based on effect on protein products:
Single-base deletion at the ABO locus, leading the a frameshift mutation responsible for the O allele
Frameshift mutation
Mutation based on effect on protein products:
Tay-Sachs disease: four-base insertion in the hexasominidase A gene
Frameshift mutation
