Younger Review Flashcards
CDNA library
- MRNA at time of harvesting
- expression of gene at specific time
- uses reverse transcription to change RNA to DNA
DNA library
-all sequenced of a genome (introns, coding regions, etc)
ELISA
- sensitive
- could be bad because it gives false positives because of sensitivity
- can feel positive about negative results
- check positives with a western blot (more specific)
What kind of probe does ELISA use?
Antigen
Long probe
Not specific, used for identifying
Short probe
Very specific
ASO
- allele specific oligo probe
- short
- specific
- recognize allele for mutation such as cystic fibrosis
Southern blot
DNA
Northern blot
RNA (MRNA)
Western blot
Analysis of protein
-quantitative
What kind of probe is used in western blot
Antibody specific to the protein of interests
What materials need to be denatured first before they can be blotted?
Protein and DNA
What are the different types of RFLPs?
SNPs
VNTRs
RFLPS
- change in nucleotide sequence somewhere in genome.
- make or abolish a fragment
- can be used for fingerprinting
VNTRs
- Fragment is longer than normal
- can test for early detection
- Huntington’s
- fragile X
- anticipation
What are the 3 thermocycle steps in PCR
- denature
- anneal
- elongation
What are the advantages of PCR to DNA cloning?
Less time
Less cost
Minute amounts of DNA required
DdNTP
Stop elongation
Used in cancer treatments
Microarray
- contain thousands of immobilized sequence (probes) on glass slides
- mRNA levels
- compare cancer to normal on a color probe
Why do ASO probes have a relatively low utility for diagnosis of diseases such as PKU due to the multitude of possible mutations that can affect the gene and cause the disease
ASO is generally used for a single gene mutation (3 nucleotide change)
-PKU has so many different possibilities for mutations so ASO is too specific for this
What are VNTRs used as?
- molecular fingerprints
- paternity testing
- uses PCR
- different VNTRs have a different paternity index, paternity cases always require several different VNTRs be used
Recurrence risk
- probability that offspring of a couple will have the genetic disease
- each reproductive event is statistically independent of all previous events
If 25% of offspring have diseases, its usually
Autosomal recessive
If 2 recessive heterozygous people are mating, what is the chance of their offspring having it
25%
Dominant heterozygous likelihood for offspring
75%
What are the 2 general types of autosomal dominant single gene disorders
- loss of function (phenotype)
- gain of function (toxic)
What gene is defected in neurofibromatosis type 1
Mutation in a cell cycle regulatory protein
What type of disorder is neurobibromatosis type 1
Autosomal dominant
An important genetic concept that is epitomized by neurofibromatosis type 1 is
Variable expression, hallmark
What ia a clinical diagnostic clue for neurofibromatosis type 1
Lisch nodules
What type of disorder is Marfan syndrome
Autosomal dominant
What gene is defective in Marfan syndrome
A mutation in the fibrillin gene
Marfan syndrome is a good example of a genetic principle called
Pleiotropy-when a single mutation affects multiple organ systems a common feature of many genetic diseases
What are the ocular abnormalities of marfan syndrome
Myopia and detached lens
What kind of disorder is thalassemias
Autosomal recessive
When gene is defective in thalassemias
Imbalance in globin chain synthesis
What is the most common single gene disorders group in the world
Thalassemias
Types of thalassemias
- alpha-insufficient synthsis of a chain
- beta-insufficient syntheiss of b chain
What is a good thing about thalassemias
Malaria resistance
Gene defect for hemophilia A and B
Blood clotting factors
What kind of disorder is hemophilia A and B?
X linked
What is the most frequent cause of death in hemophilia?
AIDs
-when they get blood transfusions, in order to protect the clotting factors in the blood the donor blood cant be treated for viruses, so AIDs sometimes will be present in the transfusion
Why can some female heterozygotes with one mutant X chromosome show symptoms of an X linked recessive disease
X inactivation
Rare cases of single gene disorders that do not manifest until later in life
Delayed age of onset
What are two examples of delayed age of onset
- Huntington’s
- myotonic dystrophy
When the same disease phenotype can be caused by mutations in different loci
Locus heterogeneity
What is an example of locus heterogeneity
Ehlers-Danlos Syndrome (EDS)
What kind of disorder is EDS
Can display several different inheritance patterns :Autosomal dominant, autosomal recessive, X linked
EDS autosomal dominant is a mutation in what
Collagen genes
EDS autosomal recessive is a mutation in what
Lysyl hydroxylase
EDS linked is a mutation in what
Copper binding protein
All genetic diseases being with this. In cases with high mortality or low fertility, it is often due to this. Immediately show up in pedigree
New mutation
Refers to diseases where the most recent generations of affected individuals show earlier onset and more severe symptoms than previously generations
Anticipation
What is anticipation usually associated with
Diseases causes by trinucleotide repeat expansions (Huntington’s, fragile x, myotonic dystrophy)
What is the most common genetic (inherited) cause of cognitive/mental impairment
Autism (fragile X)
What is another name for x inactivation
Lyonization
Inactive x chromosome can be observed by EM as a highly condensed ________ in the nuclei of interphase cells
Barr body
Recessive alleles can be concentrated in populations due to natural selection through a selective process termed ________
Heterozygote advantage
Occurs in populations with finite population size. Can be particularly rapid in small populations
Genetic drift
Relatively rare alleles are present in higher abundance in a small isolated population that goes on to colonize an area
Founder effect
Example of founder effect
More cases of ellis can crevald disease are seen in old order amish than the rest of the world
What kind of inherited disease is ellis van crevald
Rare autosomal recessive
What is the defective gene in ellis can crevald
Caused by a defective EVC gene, unknown function
