3 DNA Techniques Flashcards
why dont endogenous restriction endonucleases cleave host DNA?
DNA is methylated at recognition sites
what is a key characteristic of restriction cleavage sites?
they are palandromic with their complimentary bases
what pole does DNA run towards on a gel?
the anode, the positively charged poe because DNA is negatively charged
what is a southern blot used for?
visualizing and isolating a particular segment of DNA. a probe is used for the isolation and after membrane has been soaked in NaOH to make the DNA single stranded
can you detect deletion using souther blots?
yes, the segment will be smaller if it contains a deletion
can southern blots detect trinucleotide repeat expansions?
yes, the segment will not run as far in the gel
can a point mutation be detected by southern blot?
yes as long as it is in the restriction site
on what scale is FISH used?
to look for the presence of certain fragments of DNA on entire chromosomes
in general what is the purpose of running a northern blot?
to determine the size and amount of specific RNA molecules
what is a reason to use a DNA band shift assay?
to see if a certain protein associates with DNA. If it does, the DNA not run as far in a gel compared to when the protein is not introduced
what is DNA footprinting used for?
to see where exactly a protein associates with a specific fragment of DNA
how can you detect a single strand conformation polymorphism using PCR?
amplify the fragment that it is contained in and run it on a gel versus the wild type. It will run differently due to the change in conformation
what is the diference between genomic and cDNA libraries?
genomic is fragments of DNA straight from the genome.
cDNA library is derived from mRNA which is reverse transcribed and then cloned
