Genetic Mutations And Polymorphisms Flashcards
Mutation of the CFTR gene results in:
Chloride channel does not reach plasma membrane disrupting the movement of chloride ions
One of the specific mutations for Tay-Sachs involves:
A point mutation G to C that alters the proper slicing of the mRNA at the boundary between exon 12 and intron 12 of hexA gene
Charcot-Marie-Tooth disease (CMT) specific genetic mutation
Duplication of 1.5 million base pairs of chromosome 17 produced by misalignment during recombination. All genes are present as three copies
Charcot-Marie-Tooth disease alters the ___________ gene and is a ___________ disorder
PMP22
Neurological
VNTRs repeat polymorphisms:
14-500 bp
Tay-Sachs is a __________ inheritance
Autosomal recessive
Example of lethal mutation
Infantile Tay-Sachs
B-Thalassemia is a _____________ inheritance
Autosomal recessive
B-Thalessemia specific genetic mutation
Different point mutations affect B-globin gene and result in a decrease in the production of B-globin
Hemophilia B specific genetic alteration:
An A to G transition alters the bind of a key transcription factor needed for expression
Frame-shift mutation
Insertion/Deletion of 1-2 bp. Everything past the insertion/deletion is read in the wrong frame
SNPs
Single Nucleotide Polymorphisms
Conditional Mutations:
Depend on the environment for manifestation of the disease symptoms
Cystic Fibrosis is a ____________ inheritance
Autosomal recessive
Cystic fibrosis alters the ___________ gene and is a __________ disorder
CFTR
Lung
How does VNTR technique work in solving identity
Excluding people rather than recognizing people
Charcot-Marie-Tooth disease (CMT) results in:
Peripheral nervous system disease resulting in progressive atrophy of distal limb muscles
In a transition point mutation, a ______ is replaced by a ______
Purine, different purine
Or
Pyrimidine, different pyrimidine
B-thalassemia is alters the __________ gene and is a __________ disorder
B-globin
Blood
The number of repeats in a sequence can be used to creat a:
“Molecular fingerprint” of individuals
Nuerofibromatosis Type 1 (NF1) has a _______________ phenotype
Highly variable
Tay-Sachs is common among populations of:
Ashkenazi Jewish
Cajun
French Canadian
Most common inherited neurological disorder:
Charcot-Marie-Tooth disease
Point mutation:
Represent single base pair changes in the sequence of DNA
Huntington’s disease is the result of:
An expansion of a CAG triplet
Tay-Sachs is a deficiency:
Lysosomal storage disorder resulting from a deficiency of the lysosomal hexosaminidase A protein coded for by hexA gene
Large deletion can be a result of:
Aberrant recombination
Lack of hexosaminidase A leads to:
A build-up of GM2 ganglioside in neuronal lysosomes, causing neuron damage
Symptoms of Neurofibromatosis Type 1 (NF1)
Neurofibromas
Cafe-au-lait spots
Lisch nodules in the iris
The most common genetic mutation for cystic fibrosis:
Deletion of three nucleotides within the coding region (In-Frame mutation)
Example of conditional mutation
G6PD deficiency
In-frame mutation
Insertion/Deletion of 3 bp. Extra amino acids are inserted/deleted by remaining codons are read correctly
Mutations can be generated by:
Failure of the DNA to copy accurately
Internal/external influences of the DNA structure/nucleotides
Lethal mutations:
Cause the organism to die, often during development leading to miscarriage
Neurofibromatosis Type I (NF1) specific genetic mutation
Nonsense mutation that introduces a stop codon into the NF1 coding region. Shortened protein is unstable and rapidly degraded
Which gene is associated with Charcot-Marie-Tooth disease?
PMP22: encodes peripheral myelin protein
CFTR:
Cystic Fibrosis Transmembrane Conductance Regulator
Example of a large deletion mutation:
A-thalassemia
A-thalassemia alters the _____________ gene and is a ___________ disorder
A-globin genes
Blood
VNTRs stand for:
Variable Number Tandem Repeats (mini satellites)
CFTR function:
Chloride channel
Missense mutation:
Wrong amino acid
Tay-Sachs alters the gene _______ and is a ________ disorder
HexA (hexosaminidase A)
Neurological
Example of Loss-of-function mutation
NF-1, cystic fibrosis
The most common variant of Tay-Sachs is caused by:
A 4 base insertion in the hexA gene (frameshift) resulting in a premature stop codon (nonsense)
Hemophilia B alters the gene ________ and is a __________ disorder
Factor IX
Blood clotting
Gain-of-function mutation:
Increased protein activity, novel protein activity, or protein expressed in a novel location
Neurofibromatosis Type I (NF1) is ___________ inheritance
Autosomal dominant
Neurofibromatosis type 1 alters __________ gene and is a ____________ disorder
NF1 (neurofibromin)
Neurological (neurofibromas, learning disabilities)
Phenotype represents:
The observable character of the cell or organism
Sickle-cell disease alters _________ gene and is a ________ disorder
B-globin
Blood
STRPs are repeats of about
205 bp
Epigenetic changes are:
Alterations in phenotype without a true alteration in genotype
Loss-of-function mutation:
Function of the GENE is lost, either partially or completely
In a transversion point mutation, a ________ is replaced by a _____________
Purine, pyrimidine
Or
Pyrimidine, purine
Methylation (is/is not) a form of mutation
Is not
CODIS:
(Combined DNA Index System) is a panel of 15 VNTR loci used by the FBI
Large insertion disease:
Charcot-Marie-Tooth disease
Most severe form of Tay-Sachs
Infantile
Influences on phenotype
Genotype and environment
Polymorphism versus Mutations
Polymorphism: common variants in DNA sequence in a population
Mutations: changes in the DNA sequence of an individual
Purine:
Adenine (A) and guanine (G)
Silent mutation:
Base change that doesn’t change the amino acid
Sickle cell disease specific mutation
Missense mutation A to T transversion that changes the amino acid
Point mutations in B-thalassemia can affect:
Transcription levels of the gene (promoter region mutation)
Splicing of the gene
Amino acid sequence of the the coding region (missense, nonsense)
Stability of protein (nonsense)
Two types of point mutation:
Transitions and Transversions
Pyrimidine=
Thymidine (T) and Cytosine (C)
CNVs have repeat polymorphisms:
Greater than 1000 bp, up to 2 million bp
Consequences of point mutations:
Missense, nonsense, silent
Nonsense mutation
New stop codon
Sickle cell disease is a __________ inheritance
Autosomal recessive
An allele is a:
Variant form of a gene that was created by the occurrence of a mutation in the DNA sequence
Hemophilia B is a ____________ type of inheritance
X-linked recessive
Changes in genotype do or do not always result in changes in phenotype
Do not
Genotype represents:
The genetic constitution of an organism. It is the summation of all of the DNA within the cell or organism
Mutations are:
Changes to the nucleotides within the DNA
STRPs stands for:
Short tandem repeat polymorphisms (microsatellites)
CNVs stand for:
Copy Number Variations
Much of the inter-individual variation seen between people is attributed to:
Polymorphism
