DNA extraction - details about ethanol precipitation - (Sep/06/2005 )
Can DNA be isolated without ethanol precipitation?
E.g. with the Promega mini wizard kit.
Can you tell me the principle behind DNA precipitation using ethanol?
I think ethanol does not selectively precipitate DNA
so the degree of contamination with salt (used in buffer) is really high ,
How can this be avoided?
You need high salt (eg NaOAc) to precipitate the DNA using ethanol. After precipitating, use a 70% ETOH wash to remove the salts.
Does DNA precipitation with Isopropanol requires the salt as well?
Isopropanol uses lower salt concentration.
what is the purpose for using phenol -chloroform in DNA extraction?
Phenol/chloroform is used to purify the DNA (removing proteins, inactivating DNAses etc). The isoamylalcohol in the phenol/chloroforn is used for better seperation between phenol-layer and water layer (containing the DNA). The second chloroform step will remove all remaining phenol from your water phase.
Iam extracting DNA from mosquitoes,
how much sample should I use?(currently using 10nos/ml)
I have followed ethanol precipitation
but I could not see the white thread
of DNA on adding ethanol.
You need to have a high concentration of DNA to see it precipitate in solution. I assume you are performing some form of a lysis step prior to all this?