Hi there

for PCR a 260/280 ratio of of 0.77 is perfectly acceptable:1.8 to 2.0 is ideal but anything above 0.7 normally works well all other things being equal

Regarding concentration PCR with genomic DNA tends to work with 10ng to 100ng so 1ul if your reaction at 72ng/ul should suffice 

Hi there

for PCR a 260/280 ratio of of 0.77 is perfectly acceptable:1.8 to 2.0 is ideal but anything above 0.7 normally works well all other things being equal

Regarding concentration PCR with genomic DNA tends to work with 10ng to 100ng so 1ul if your reaction at 72ng/ul should suffice 

i agree with Laurence. Just need to do calculation and see the amount of final dna concentration in pcr template. We use to got 100 ng or less. Also dna is stable...

I suppose that you can run the PCR and get the desired DNA amplified with the concentrations you have.  You can run a few reaction varying the concentrations of template DNA.  Ensure that other components of the reaction mixture like Mg ions, ATP etc. are adequate enough if you are preparing the reaction mix.

Good luck.

Hi there

a 260/280 ratio if the end application is PCR is perfectly acceptable: Generally speaking whilst 1.8 to 2.0 is ideal anything above 0.7 is usually fit for purpose and when it comes to PCR would rarely cause problems in and of itself; unless of course there are other confounding factors

I have been performing PCR since the early 90s and I would NEVER contemplate removing protein for PCR with a ratio like that. Be careful about conjecture not rooted in practical experience: PCR is highly robust and the principal factors which cause failure I factors like primer design; secondary structure in your target and inhibitors, particularly salts & organics which are potentially indicated by 260/230 ratios of < 1.0

Thus, my own experience would suggest the following:

1. with a 260/230 ratio of 0.77 and a concentration of 75ng/ul simply use 1ul of your DNA. Amplification from gDNA works between 10-100ng and 20-50ng is a good place to start and if your product is clonal such as a plasmid where high copy number applies as little as 1ng should amplify well

2. Do however pay attention to the 260/230 ratio given your 260/280 ratio is acceptable: < 1.0 indicates salts and/or organics like phenol or Trizol if that is your chosen method of extraction and simple re precipitation with ethanol followed by a 70% ethanol wash should get that ratio above 1.0 (and preferably >1.5) which indicates negligible contaminants that will (or could) inhibit your PCR (not protein)

3. In terms of 260/280 ratios that could indicate too much protein we normally consider re extraction @ 1.8

Good luck

Hi there,

I would suggest you to run the PCR assay first and to consider the issue of the DNA template if it doesn't work fine. I'm used to run PCR on very crude bacterial and yeast cell lysate without major problem (I guess 260/280 ratio in there is not optimal though).

Hi Again

this is a late addition to my previous comments: In essence I agree with Dominique

Yesterday in fact I extracted or rather liberated genomic DNA from mouse tissue simply by heating with 0.05M NaOH for 15 min; neutralising with Tris and then simply allowing the gDNA to leach from the broken down/hydrolysed tissue remnant over night at 4C before commencing PCR today

I know from experience that this nearly always works so to qualify my prior comment about 260/230 and to affirm what Dominique has presently said:

1. Yes a 260/280 ratio > 0.6 is ideal in terms of maximum signal to noise and specificity and ideally a 260/230 ratio of > 1.0 promotes your chances of applications like RT working well, but for simple PCR from genomic DNA especially using modern polymerases a crude genomic lysate will often work 

2. Moreover, like Dominique, for simple PCR I do not even look at 260/280 & 260/230 ratio as they would by simple consideration with reference to a crude genomic lysate be less than optimal but for standard PCR from genomic DNA in the context of modern polymerases this doesn't matter most of the time (for other applications however like RT or RNA amplification it definitely does)

I would also add that boiling up bacterial transformant colonies - formally referred to as 'colony cracking' - also can work for basic PCR