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AVAILABLE MOLECULAR CYTOGENETIC TECHNOLOGIES (ABOUT (Advantage (Provide…
AVAILABLE MOLECULAR CYTOGENETIC TECHNOLOGIES
ABOUT
Alternative to chromosomal banding
Widely applies in basic biomedical research
Proven effective in diagnostics
Advantage
Provide either an on chip scan of the whole genome at extremely high resolution or visualization of single peculiar genomic loci
Capable of analyzing genome organization, structure and behaviour in single cells at DNA sequence level
Used for molecular diagnosis of chromosomal abnormalities
FISH
Techniques
I-FISH with wcp
Painting chromosome territories
ADV
: Identification of nuclear chromosome territories
LIMIT
: Chromosome territories are ambigous, no additional information
mFISH
Multicolor I-FISH with > 2 probes labeled by different fluorochromes/ligands
ADV
: Analysis of several targeted genomic loci
LIMIT
: Difficult to distinguish between artifacts and aneuploidy/polyploidy
I-FISH with site-specific probes
Painting specific euchromatic genomic loci
ADV
: Visualize small specific euchromatic genomic loci
LIMIT
: Low hybridization efficiency, numerous artifacts
MFISH
Simultaneous visualization of the complete set of chromosomes in an interphase nucleus
ADV
: All chromosomes territories are simultaneously seen
LIMIT
: Exceedingly sophisticated analysis; data poorly interpretable
I-FISH with centromeric probes
ADV
: High hybridization efficiency and chromosome specificity
LIMIT
: Signal associations, impossible to analyze chromosomes 5, 13, 14, 19, 21, 22; heteromorphism
I-FISH on interphase nuclei painting pericentromeric regions
ICS/MCB
Chromosome-specific MCB generated on interphase nuclei
ADV
: Visualization of whole banded interphase chromosomes in their integrity
LIMIT
: Relative complexity of the analysis
mFISH/QFISH
ADV
: Distinguishes between FISH artifacts and aneuploidy
LIMIT
: Difficult to distinguish between artifacts and aneuploidy/polyploidy
mFISH + QFISH digitalization of FISH signal
About
Can be performed with either
centromeric
or
telomeric
DNA probes
Centromeric probes
: As an integral part of diagnostics in medical genetics, oncology and reproductive medicine
Telomeric probes
: Analysis was only described in few nuclear organization study
Research Involvement
: In fields of Chromosome biology studying genome organization, evolution, behaviour and variation in health and disease.
CGH
Compares quantitative differences betweeen individual genomes
Restricted to analysis of losses/gains of chromosomal loci
Comparative Genomic Hybridization
Types
Array CGH
Provide for a resolution up to nucleotide level
Poorly applicable for studying chromosomes of a cell
Standard CGH
Both have been involved in detecting chromosome aberrations in single cells of preimplantation embryo
PNA & PRINS
PNA
Smaller size
: Several advantages over conventional molecular cytogenetics probes
Poor availability
: Unable to evaluate
in situ
hybridization
Restricted for studying centromeric and telomeric repetitive chromosomal DNA
PRINS
Based on polymerase reaction
Useful for case-control studies of newly discovered phenomena
Usually shows almost the same result as FISH
Limitation
: Available probes are oligonucleotides for pericentromeric/heterochromatic and few euchromatic regions (poorly reproducible)