The Living Database

I am a software engineer by profession (i.e. a 'computer geek'), so perhaps it is inevitable that I would look at the human body from an information-processing point of view.

When a new human being is conceived, he or she consists of only one tiny microscopic cell. How does that single cell grow into a complete body? As that one cell becomes many, how does each one 'know' whether it is supposed to be bones, or skin, or parts of the eye or lung or heart, all arranged in the correct places?

As with any building project, the first essential step is to have a plan, a blueprint. For a human being, this blueprint is called the 'genome'. Every cell in your body has a copy of this blueprint, 'written' on the long chain molecule called DNA (deoxyribonucleic acid) that makes up your chromosomes.

Only in the last half of the 20^th century have we begun to understand this blueprint. Before then, people could only guess that such even existed.

What biologists have learned so far displays what software engineers would call amazingly 'elegant' design.

At the lowest level, the genome is built from just four different chemicals, called 'bases' (adenine, thymine, cytosine, and guanine), chemically bound to a molecular backbone. These bases are combined into groups of three, called 'codons'. Codons are combined into groups of various length called 'genes'. The average gene has about a 1,000 codons. Genes of related function are often grouped, together with genes that control whether they are active or not, into 'operons'. Operons are combined into chromosomes. And all the chromosomes make up the genome. The entire human genome includes about one billion codons, or three billion bases.

Notice how similar this organization is to a written language. A base is like a letter. A codon is like a word, a gene like a sentence. An operon can perhaps be likened to a paragraph, and a chromosome is like a chapter. And the genome would then be the entire book.

Actually reading this 'book' is another matter. By studying chromosomes under a microscope, a skilled technician can tell a few basic things about the person they came from, like whether this person is male or female — one of the chromosomes looks distinctly different. It is also possible to recognize some types of birth defects. For example, Down's syndrome can be recognized by a certain extra chromosome.

But until recently, that was about it. It was like someone who had lost his glasses trying to read a book: he might be able to tell how long the chapters are, or notice that a page was torn out, but that was all.

In recent years biologists have learned to read the 'letters'. That is, with much high tech equipment and sophisticated techniques, they can find exactly which bases make up almost any given section of the genome. The 'book' is so long that it's taken years to (almost) decipher with the help of supercomputers. But for the most part, it's like reading a book written in a foreign language; just knowing the alphabet isn't enough.

We do understand the function of one important part of the human genome: some sections control the manufacture of proteins. Proteins are key chemicals in your body, made of smaller pieces called amino acids; often thousands of them, strung together in a long chain. This then folds to make the protein.

There are 20 amino acids, and the sequence in which they are assembled determines the structure and function of the resultant protein. A gene is that stretch of DNA coding for one particular protein, with each of the codons in that gene coding for one amino acid.

This only accounts for a small percentage of the human genome. The figure given varies, but evolutionists generally say that the remainder, 90% or so, must therefore be left-overs ('junk' DNA) from earlier stages of evolution, no longer used or needed. But this is an argument based on ignorance: 'We don't know what its purpose is, therefore it has no purpose.' It would seem more reasonable to withhold judgment until there has been more research, especially considering that it is only in the last few years that we have begun to understand the function of the protein-making sections.

There are plenty of parts in my car that I don't understand. But I do not therefore conclude that they are useless leftovers from an earlier era in automobile design, carelessly included despite no longer having any purpose.¹

Computer experts often strive for what we call an 'elegant' design. By that we mean a system which solves a complex problem, but which at heart is simple and consistent. The ideal design uses the fewest different pieces, and combines them in consistent ways.

Look at the elegance of the genome. At the lowest level, there are only four different bases. These are always combined in groups of three. Never two, never four, always three.

But why three bases in a codon, you might ask? What's special about that number? Well, there are 20 different amino acids in human proteins. One base to specify each amino acid would not be enough; there are only four different bases, but 20 amino acids. Two would give 4 x 4 = 16 possibilities, still not quite enough. Three is enough: 4 x 4 x 4 = 64, which of course is more than 20.² Four would have been overkill, far more possibilities than necessary.

And of all the billion billion possible ways that 64 codons could code for 20 amino acids, ours turns out to be among the very best (see DNA below).

In short, this is exactly the sort of design that a computer expert would admire. A minimal number of different pieces to keep it simple, combined into groups of exactly the right size to be just enough to express the desired information with no waste, and with a consistent method of interpreting the data.

Could such a system have arisen by chance? The scheme is so neat and tidy. Random processes rarely result in neatness. Few computer systems designed by experts display as much elegance and sophistication as we find in the human genome.

How much information is in the human genome? If we were to type it out, one letter for each of one person's three billion bases, it would take 500,000 pages — single-spaced, both sides of the paper. Stored on a computer, using one byte (the amount for storing a letter or digit of text) per base, we would need three billion bytes, or three 'gigabytes'. As little as five or six years ago, only the largest computers could handle this much data. And actually doing anything with this amount of information is another story. The most complex computer programs written today — compilers, the programs used to write other programs — now require as much as 150 million bytes. This is about one twentieth of the amount of information in the human genome — i.e. in each cell.

In short, it is just within the last few years that human beings have reached the point where we can even hope to process the amount of information that is contained in a human genome. Our most sophisticated 'machines' — computer software — are just now reaching the same scale.

DNA is vastly more efficient at storing information than is our present technology. In the amount of DNA which would fill a pinhead, one could store the information which, typed out, would make a pile of paperback-size pages so high that it would reach from here to the moon 500 times!³

It is perhaps possible that people alive now may live to see the day when human beings will create a code as sophisticated as the blueprint for a human body. However, our body is much more than a code. The blueprint is only expressed within an existing cell which has all the machinery to manufacture the proteins and other components specified by the code. Constructing even a single cell 'from scratch' would be a very, very tall order.

If mankind ever achieves such a feat, it would just underline the incredible intelligence of our wonderful Creator God, who created all kinds of living things in just a few days during Creation Week.

References and notes

1. Mutations in non-coding DNA have been found to cause cancer, which suggests that this DNA is very important.
2. The extra codes are not wasted. There is more than one code for different amino acids. The extra codes make the system robust so that mutations (copying errors during reproduction) which change one base are less likely to change the amino acid coded for.
3. Gitt W., Dazzling Design in Miniature, Creation 20(1):6, 1997.

The statistics on human genetics used in this article all came from:
Primer on Molecular Genetics, by the United States Department of Energy Human Genome Program, Washington D.C., USA, June 1992.

DNA's chosen language ... an evolutionary conundrum.

Evolutionists have often pondered the 'why' of the actual DNA code, the 'language convention' universal to all living things, which prescribes which triplet codon specifies which amino acid. There are many other possible conventions which could have been used, but it has now been discovered that the existing one 'resists error better than a million other possible codes'.¹

Such incredible error-proof efficiency should shout 'design' to them, but instead they see it as evidence that the choice of code must have been shaped by natural selection, i.e. approaching its current perfection by trial and error.

But herein is a conundrum for them. As some have pointed out, once there was an existing language convention, no matter how error-prone, any subsequent changes by chance would have been 'like switching the keys on a typewriter, leading to hopelessly garbled proteins'.¹ Thus, however the code began is how it would have stayed. In the evolutionary scenario, that means that a random origin just 'happened' to fluke odds of a million or so to one to arrive at the best possible code. This is good evidence against evolution — the code convention is clearly the result of deliberate, creative design.

Reference

1. Tracking the History of the Genetic Code, Science 281:329-331, July 17, 1998.

The chicken or the egg?

The complex mechanisms needed to decode the DNA, and to proof-read it for errors are themselves proteins, coded in the DNA. Thus we have the classic chicken and egg problem: since proteins are needed to read, check and manufacture DNA, and DNA is needed to make proteins, which came first in the alleged evolutionary process?

The obvious answer is that they did not evolve, but were created together. Some have tried to suggest that originally, something like RNA (a chemical related to DNA) was able to be both code and replicator, i.e. chicken and egg. But there are huge problems with this and related suggestions:

See CEN Technical Journals:

10(3):300-314, 1996;
11(1):4-6, 1997;
12(3):263-266, 281-284, 1998;
13(2):5-6, 124-127, 1999.