How many Salmon cells does it take
to make a DNA Tube?
The DNA Tube is salmon testis DNA from Sigma Company. You can find the purity specifications in the Sigma catalog. I don't know how they isolate it.dnatubeart
There's anywhere from 2 to 4 mg of DNA in the tube. In double stranded DNA, I figured a GC base pair with two phosphates and two deoxyriboses to have a MW (Molecular Weight) of 609, and an AT to have a MW of 615. Let's call it an average MW per base pair of 600 (to make the calculations easier).
I don't know how big the salmon genome is, so let's go with the human genome of about 3 billion base pairs. A molecule of 3 billion base pairs with each base pair having a MW of 600 would have a molecular weight then of 3 billion X 600 = 1.8 trillion (1012)
That means 1.8 trillion grams per mole.
A mole is 6 x 1023 molecules.
Each nucleated, diploid human cell has on average 2 "molecules" of DNA, each with a molecular weight of 1.8 trillion. (I'm not sure if the 3 billion base pair estimate for the human genome is the diploid genome or the haploid genome. Let's assume that 3 billion base pairs is for the haploid genome. That means each cell has 2 "molecules" of DNA each with a MW of 1.8 trillion, for our calculations.)
How many moles does it take of something that weighs 1.8 trillion grams per mole to make 2 milligrams? or better yet,
How many human cells does it take?
x cells = 2 milligrams DNA x (1 mole DNA/1.8 trillion grams DNA) x (6 x 1023 molecules DNA)/mole DNA x (1 cell/2 molecules DNA)
and if my math is right, that ends up to be 360 million cells.
A technical information sheet from Qiagen that lists the nucleic acid content of the typical human cell as approximately 6 picograms.
That's 6 x (10-12) grams DNA/human cell.
To calculate the number of cells required to yield 2 milligrams:
x cells = 2 x (10-3) grams DNA X 1 cell/(6 x 10-12) g DNA
= .33 x 109 = 3.3 x 108, or 330 million cells.
The first estimate was 360 million cells.