Not only is DNA chemically stable and can last for years, has internal redundancy, but it is remarkably compact. DNA is an evolutionarily optimal data storage medium.

To put it into context, each cell in your body contains 6 billion base pairs of data (two copies of your genome). Each base is one of 4 bits, so that’s 4^6000000000 of data in each cell. Your body has ~37 trillion cells [1]. A person is about the size of a rack (well, maybe 10-15U by volume), so that’s 3.7e13 * 4^6e9 bits per rack.

A petabyte is 8e15 bits.

That’s a lot of data storage capacity in a small space. Moreover, there is the potential for introducing more synthetic bases to increase the 4 to 6.

https://www.ncbi.nlm.nih.gov/m/pubmed/23829164/

Minor correction: each base pair is one of 4 values (A, T, G, C), so each base pair is equivalent to 2 bits of data, which gives a number half of what you quoted.

Yes, I misworded it and gave the wrong numbers. I gave the number of possible combinations in a genome, which is 4^6e9. That’s obviously not the number to compare (and a slightly embarrassing mistake).

With 6 gigabases per cell and 2bits per base, the storage capacity is 12 gigabits (1.5 gigabytes) per cell. And with 37 trillion cells (3.72e13) in a human body, that’s 3.72e13 cells * 1.5e9 bytes per cell which is 5.58e22 bytes per person or 55 zettabytes. This seems like a more reasonable number.

8 if you include artificial base pairs (P, Z, B, S)

The number of bits is the logarithm of possible cases; there are only two bits needed to describe the four bases, and only 12 billion bits needed to describe the 4^(6e9) possible configurations of data.

so in the matrix we'll really be hard drives, not batteries

Kind of like bags of bitcoin really.

Favourite comment in a long time

Moreover cell contains mostly other stuff than a nucleus so that's another factor of 10 or so. And human body has a lot of 'empty' space - lungs, stomach, veins, collagen, bones,....

Another minor correction: Each base pair is one of 4 things, so 2 bits of information. Each base is half of a base pair so can really only claim 1 bit of information.

Of course even when you said base you did the math with # of base pairs, so it doesn't really matter.

No, that is not correct. While each base is half of a base pair, each pair is NOT reversible. At each position along one strand you have 4 options, so each base encodes 2 bits. Even though A always pairs with T and G with C, which strand each base is on matters, so in other words if you have pair "A-T" followed by "G-C" that is very different from "T-A" followed by "C-G".

You have a problem with your counting. Each location can be in one of four possible states:

T-A

A-T

G-C

C-G

That location, using 2 base's, encodes 4 possible values, i.e. 2 bits. I.e. 1 bit per base.

It's mentioned in the article before the ATGC paragraph

""Under the right conditions, DNA can last much longer than current archival storage technologies that degrade in a matter of decades. Some DNA has managed to persist in less than ideal storage conditions for tens of thousands of years in mammoth tusks and bones of early humans, and it should have relevancy as long as people are alive.""

But that doesn't explain storage density. And biological DNA has mechanisms to survive in a cell but these synthetic DNA's might be standalone.

One other suspect thing about that is that the DNA in a body is essentially replicated across every single cell, which means maybe that the DNA from 10,000 yeras ago has just survived as a rule of statistics over any individual durability

I wonder if you could make separate 'zip/unzip' stations to compress/decompress them with histone proteins, like the body does.

https://en.wikipedia.org/wiki/Histone