Application of molecular techniques in genetics Flashcards
In MolBio, when we speak of genetics, we are specifically
dealing with______
Human Chromosome
Refers to the complete set
of the chromosomes in the cells of the organism.
- Studying the human chromosome will be based on its____
Karyotype or karyotyping
- Early development of this technique uses Radiolabeled
probes as the target label. - Because of the harmful effect of using radioactive agents, fluorescence probes are used.
IN SITU HYBRIDIZATION (ISH)
- used for the labeled gene or target that is in the reagent.
- tagging technique on how we add the
probe in the sample.
Nick Translation
used to replace some nucleotides
of DNA sequences
DNA POL I
stage of the cell is arrested.
- o Advantage: Cell culture is not required in interphase FISH, which is commonly used in he study of the prenatal samples, tumors, and
hematological malignancies.
o Much rapid diagnosis
Interphase FISH
o Designed to mark the entire chromosome of interest.
- useful for deciphering cytogenetic aberrations that are difficult to resolve on morphological grounds, such as
marker chromosomes of uncertain nature or complex changes.
o Uses many probes from a single chromosome and based on that single chromosome, there are lots of unique DNA associated with it.
o Advantage: one of the best assay for looking for any rearrangement in the chromosome.
WCP (Whole Chromosome Painting)
- Combines binary ratio labeling and
color-changing karyotyping.
o Much more automated in the sense that it uses a computer-assisted system.
o Profile is already fixed in the system, and it will just be compared.
o One chromosomal change is detected at a
time
MFISH (Multicolor- FISH)
o Main Advantage: observe multiple
chromosomal aberrations/changes.
SKY (Spectral Karyotyping)
o Uses a telomere probe which will recognize six base repeats which are present at the ends of all chromosomes.
o Advantage: Used as a confirmatory assay
because it can confirm the presence as well as
the absence of telomeric regions.
ALL-TELOMERE-FISH
o Compare the DNA content of differentially
labeled normal from abnormal cell population To identify if there is a change on the said
chromosome.
Comparative Genomic Hybridization
MAIN APPLICATION OF FISH
- DIAGNOSIS
- PROGNOSIS
- EVALUATE REMISSION OF DISEASE
Inherited diseases or Mutations
Diagnosis
- If there is a presence or absence of mutated gene
Prognosis
Repeated condition
- Evaluate Remission of Disease
- More specific
- Distinguish one disease from another.
- Detect disease cells more easily and rapidly without
requiring living cells. - Quantitate through automated methods.
- Less labor-intensive technique
ADVANTAGES OF FISH
With a microscope, it’s possible to get some indication of age sex and race from hair. Comparing hairs allows police to identify people, with an error rate of only one in 4500.
Hair
Age, sex, race, and sometimes medical history can be determined from bones
Bone
Fingerprint evidence was introduced in the late
1800s despite much skepticism. It took decades before fingerprints were routinely used in police and court matters.
o Disadvantage: easily removed
Fingerprints
o Considered as the best sample
o Blood typing based on these four groups can be a
powerful tool for resolving legal matters.
o But with only four possibilities per person, there are
many cases in which blood typing is not helpful.
o More blood groups have been discovered over the
past 100 years, but even these cannot provide the
same level of identification as DNA testing
Blood
can be recovered from blood, semen, saliva, bone, teeth, or microscopic flecks of skin or other tissues.
DNA
o Chewing Gum
o Stamps and Envelopes
o Penile Swabs
o Washed Stains
o Doorknobs
o Toothbrushes
o Sanitary Pads
o Tooth Pulp
o Sweaty Clothing
o Telephones
o Bone Marrow
o Hairbrushes
Types of objects where DNA may be found
o 2-5 repeats are called _____ DNA which can
survive degraded DNA
Micro-satellite
9-10 repeats are called_____
Mini-satellite
