Molecular Genetics Methods Flashcards
Basics Principles:
Method for Cleavage of the DNA
Restriction endonucleases
Basics Principles:
Method for Amplification
PCR
Basics Principles:
Method for Separation and visualization
Electrophoresis
Basics Principles:
Method for Visualization by hybridization (using probe)
Blot (southern) / Microarray / FISH
Basics Principles:
Method for Sequencing
Sanger / NGS
Detection of SNV: Allele specific hybridization and amplification - Which methods are used here?
Allele specific hybridization: Southern blot, microarray Allele specific amplification: PCR
Detection of SNV: What is PCR-RFLP?
3 steps:
1) PCR amplification of DNA sequence of interest.
2) Cleavage of PCR product by allele specific restriction endonuclease.
3) Gel electrophoresis to identify of cleavage pattern (genotype).
What is Southern Blot?
A procedure for identifying specific sequences of DNA, in which fragments separated on a gel are
transferred directly to a second medium on which assay by hybridization (i.e., by a probe) may be carried
out.
What is Southern Blot used for? examples
Southern Blot is used for:
− Genetic testing, e.g., in homologous alleles
− Restriction fragment length polymorphisms (RFLPs)
− Variable number of tandem repeats (VNTR)
What is ASO Test?
Allele-Specific Oligonucleotide (ASO) Test:
ASO probes have the ability to reliably detect single nucleotide changes, unlike Southern Blot which is
unable to distinguish small changes in the DNA.
What is ASO Test used for? example
Cystic Fibrosis as ASO test usage:
-Oligonucleotide probe (ASO) is complementary to the exact DNA sequence of the allele with the 508
deletion.
-DNA is obtained from all family members and spotted onto a Southern hybridization filter.
-Filter is probed with a radioactive ASO.
-Hybridization of the ASO to the filter is indicated by a spot on the autoradiogram, which indicates the
presence of the 508 allele.
What can ASO be combined with to detect 508 deletion in carriers Cystic Fibrosis?
Pedigree analysis of Proband’s Family
What is DNA Microarray ?
DNA microarray (gene chip, DNA chip, or biochip): either measures DNA or uses DNA as a part of its detection system. In each of the spots in this array, a known DNA sequence or gene is orderly arranged.
What are the types of DNA microarray?
types of DNA microarray:
- cDNA microarrays- uses complementary DNA strands formed by transcription of mRNA
- SNP microarrays- used to detect variants within a population
What are examples of Polymerase Chain Reaction types?
3
examples of Polymerase Chain Reaction types:
- RT-PCR
- qPCR
- MLPA
Reverse Transcriptase Polymerase Chain Reaction (RT-PCR):
Used for? How (Generally)?
RT-PCR is used for the analysis of mRNA expression. by reverse transcription of mRNA (less stable to analyze) a cDNA (copy DNA) can be analyzed.
Real-Time / Quantitative PCR (qPCR):
Used for? How (Generally)?
• Used to detect the PCR product as it is produced (as the fluorescent signal is generated), thus follow the
reaction in real-time.
• This allows accurate quantification of the amplified DNA by means of fluorescence measurements.
• Enables both quantitative analysis of DNA,
as well as the determination of the amount of RNA.