Dazzling design in miniature: DNA information storage
The cells of the human body can produce at least 100,000 different types of proteins, all with a unique function. The information to make each of these complicated molecular machines is stored on the well-known molecule, DNA.
We think that we have done very well with human technology, packing information very densely on to computer hard drives, chips and CD-ROM disks. However, these all store information on the surface, whereas DNA stores it in three dimensions. It is by far the densest information storage mechanism known in the universe.
Let’s look at the amount of information that could be contained in a pinhead volume of DNA. If all this information were written into paperback books, it would make a pile of such books 500 times higher than from here to the moon! The design of such an incredible system of information storage indicates a vastly intelligent Designer.
In addition, there is the information itself, which is stored on DNA, and transmitted from generation to generation of living things. There are no laws of science that support the idea that life, with all its information, could have come from non-living chemicals. On the contrary, we know from the laws of science, particularly in my own area of expertise, that messages (such as those that we find in all living things) always point back to an intelligent message sender. When we look at living things in the light of DNA, Genesis creation makes real sense of the scientific evidence.
Addendum to Creation magazine article: calculations by Dr Gitt
The greatest known density of information is that in the DNA of living cells. The diameter of this chemical storage medium is d = 2 nm, and the spiral increment of the helix is 3.4 nm (1 nm = 10-9 m = 10-6 mm). The volume of this cylinder is:
V = h × d² × π⁄4
= 3.4 × 10-6 mm ×(2 × 10-6 mm)² × π⁄4 = 1.068×10-19 mm³ per winding.
There are 10 chemical letters (nucleotides) in each winding of the double spiral (= 0.34 ×10-9 m⁄letter), giving a statistical information density of:
r = 10 letters ÷ ( 1.068×10-19 mm³) = 0.94 × 1018 letters per mm³.
This packing density is so inconceivably great that we need illustrative comparisons.
First: What is the amount of information contained in a pinhead of DNA? How many paperback books can be stored in this volume?
Example: The paperback Did God Use Evolution? has the following data:
Thickness = 12 mm, 160 pages, LB = 250,000 letters/book
Volume of a pinhead of 2 mm diameter (r = 1 mm):
VP = 4⁄3 πr³ = 4.19 mm³
How many letters can be stored in the volume of 1 pinhead?
LP = VP × r = 4.19 mm³ × (0.94 × 1018 letters/mm³) = 3.94 × 1018 letters
How many books can be stored in the volume of 1 pinhead?
n = LP⁄LB = 3.94 × 1018 letters ÷ (250,000 letters⁄book) = 15.76 × 1012 books
What is the height of the pile of books?
h = 15.76 × 1012 books × (12 mm⁄book) = 189.1 × 1012 mm = 189.1 × 106 km
How many times the distance to the moon is this?
Distance to the moon M = 384,000 km
m = h/M = 189.1 × 106 km ÷ 384,000 km = 492.5 times
[Update, 2 September 2010: how many 2 TB hard drives can be stored in the volume of 1 pinhead?
This is simply a division of the information capacity of the pinhead of DNA and that of the hard drive:
(3.94 × 1018) ÷ (2 × 1012)
≅ 2 million]
Secondly: The human genome has 3 × 109 letters (nucleotides). In body cells there are 6 × 109 letters.
The length of the genome LG is given by
LG = (0.34 × 10-9 m/letter) × 3 × 109 letters = 1.02 m
The volume of the human genome is
VG = LG⁄r = 3 × 109 letters ÷ (0.94 × 1018 letters/mm³) = 3.19 × 10-9 mm³
Volume of a pinhead of 2 mm diameter: V = 4⁄3 πr³ = 4.19 mm³
How many human genomes could be contained in 1 pinhead?
k = 4.19 mm³ ÷ (3.19 × 10-9 mm³) = 1.313 × 109 times
These are the genomes of more than thousand million people or one fifth of the population of the world.
Thirdly: A huge storage density is achieved, manifold greater than can be attained by the modern computers. To grasp the storage density of this material, we can imagine taking the material from the head of a pin with a diameter of 2 mm and stretching it out into a wire, which has the same diameter as a DNA molecule. How long would this wire be?
Diameter of the DNA molecule d = 2 nm = 2 × 10-6 mm (radius r = 10-6 mm)
Cross-section A of the DNA molecule:
A = r² p = (1 nm)² p = (10-6 mm)² p = 3.14 × 10-12 mm²
Length of the wire LW = Volume of the pinhead VP / Cross-section A
LW = VP/A = 4.19 mm³ / (3.14 × 10-12 mm²) = 1.33 × 1012 mm = 1.33 × 106 km
Length of the equator = 40,000 km
k = 1.334 × 106 km/ 40,000 km = 33.3 times
If we are stretching out the material of a pinhead into a wire with the same thin diameter as a DNA molecule it would have a length more than 30 times around the equator.
These comparisons illustrate in a breath-taking way the brilliant storage concepts we are dealing with here, as well as the economic use of material and miniaturisation. The highest known (statistical) information density is obtained in living cells, exceeding by far the best achievements of highly integrated storage densities in computer systems.