Quantitating DNA - How they did it back then? (Feb/15/2009 )

Dear all,

We now know that DNA with a concentration of 50ug/mL has an OD of 1.0 at 260nm and this value helps us determine our sample's DNA concentration.

Can anyone shed light or provide links as to how scientist arrive at that relationship? If it's by a standard curve, how did they prepare their DNA concentrations to plot the graph?

Thanks.

I'm willing to tack the challenge.
But why dos it matter?
Why don't you take it for granted?
Do you check every math axiom before using it?

Maybe they measured the weight of DNA. The DNA pellet should have mass right?

Then using that, they dissolve in fixed volume and look at Ab260 .

Work it out in reverse: take a range of DNA samples with different ODs, then determine how much DNA (weight) is in each.

or you can run an agarose gel electroforesis, with serial dilutions to to compare the concentration with another method