Lesson 4 - Southern Blotting + Hybridization Method Flashcards
- devised by Edward Southern in 1975
- DNA fragments separated on a gel
- blotted to a charged surface/membrane
- hybridized with a DNA probe
souther blotting + hybridization
devised southern blotting
Edward Southern (1975)
what is done to the DNA in southern blotting
separated on a gel
how is the DNA fragments separated
blotting to a charged surface/ membrane
example of charged surface/ membrane
nitrocellulose membrane
used to find gene of interest
DNA probe
how is the location of DNA+probe on the filter detected
by autoradiography
autoradiography can detect ~5 µg single copy sequence
high sensitivity
what can the autoradiography detect
~5µg single copy sequence
applications of souther blotting/hybridization
- RFLP mapping
- forensic investigation
- genetic screening
RFLP
restriction fragment length polymorphism
Steps in Southern Blotting + Hybridization
- restriction digestion
- electrophoresis
- blotting and denaturation
- hybridization with radioactive probe
- autoradiography
- DNA samples to be tested are prepared from the approprate sources
- restriction enzyme is added to the samples of DNA to produce restriction fragments
restriction fragment preparation
what is produced when a restriction enzyme is added to the samples of DNA
restriction fragments
- the mixtures of restriction fragments from each sample are separated by this
- each sample forms a characteristic pattern of bands
electrophoresis
- capillary action pulls an alkaline solution upward through the gel and through a sheet of nitrocellulose paper laid on top of it
- transfers the DNA to the paper and denaturing it in the process
- single strands of DNA stick to the paper, positioned in bands exactly as on the gel
blotting