Unraveling DNA's Design
Recent research into the structure and workings of genes and DNA has revealed incredible evidence of God's wonderful design. Dr. Jerry Bergman, professor of science at Northwest College, Archibold (Ohio) has recently published an excellent technical paper in the Creation Ex Nihilo Technical Journal, 1 detailing how genes manufacture plants and animals.
We have excerpted portions of his report for this article.
At the moment of conception, a fertilized human egg is about the size of a pinhead. Yet it contains information equivalent to about six billion "chemical letters." This is enough information to fill 1000 books, 500 pages thick with print so small you would need a microscope to read it!
If all the chemical "letters" in the human body were printed in books, it is estimated they would fill the Grand Canyon fifty times! 2
This vast amount of information is stored in our bodies' cells in DNA molecules and is coded by four bases-adenine, thymine, guanine and cytosine. The key to the coding of DNA is in the grouping of these bases into sets that are further sequenced to form the 20 common amino acids. Together, these genetic codes form the physical foundation of all life.
We've all been exposed to the basic concepts of DNA and its double-helix structure in our high school biology classes. Perhaps you remember being taught that cells divide through the "unzipping" and subsequent replication of the double helix. In all likelihood, though, the incredible evidence of design in this process was not discussed.
A Complex Engineering Puzzle
Suppose you were asked to take two long strands of fisherman's monofilament line-125 miles long-then form it into a double-helix structure and neatly fold and pack this line so it would fit into a basketball.
Furthermore, you would need to ensure that the double helix could be unzipped and duplicated along the length of this line, and the duplicate copy removed, all without tangling the line. Possible?
This is directly analogous to what happens in the billions of cells in your body every day. Scale the basketball down to the size of a human cell and the line scales down to six feet of DNA.
All this DNA must be packed so the regulator proteins that control making copies of the DNA have access to it. The DNA packing process is both complex and elegant and is so efficient that it achieves a reduction in length of DNA by a factor of 1 million. 3
When the cell needs to divide, the entire length of DNA must be split apart, duplicated, and repackaged for each daughter cell. No one knows exactly how cells solve this topological nightmare. But the solution clearly starts with the special spools on which the DNA is wound.
Each spool carries two "turns" of DNA, and the spools themselves are stacked together in groups of six or eight. The human cell uses about 25 million of them to keep its DNA under control. 4 (As shown in Figure 3 on the previous page, DNA is wound around histones to form nucleosomes. These are organized into solenoids, which in turn compose chromatin loops. Each element in this complex, yet highly organized arrangement is carefully designed to play a key role in the cell replication process.)
The details of cell replication are too complex to be described in detail here. A simplified outline is given below to illustrate the incredible process involved: 5
1.Replication involves the synthesis of an exact copy of the cell's DNA.
2.An initiator protein must locate the correct place in the strand to begin copying.
3.The initiator protein guides an "unzipper" protein (helicase) to separate the strand, forming a fork area. This unwinding process involves speeds estimated at approximately 8000 rpm, all done without tangling the DNA strand!
4.The DNA duplex kinks back on itself as it unwinds. To relieve the twisting pressure, an "untwister" enzyme (topo-isomerase) systematically cuts and repairs the coil.
5.Working only on flat, untwisted sections of the DNA, enzymes go to work copying the strand. (Two complete DNA pairs are synthesized, each containing one old and one new strand.)
6.A stitcher repair protein (DNA ligases) connects nucleotides together into one continuous strand.
Read and Write
The process described above is only a small part of the story. While the unwinding and rewinding of the DNA takes place, an equally sophisticated process of reading the DNA code and "writing" new strands occurs. The process involves the production and use of messenger RNA. Again, a simplified process description: 6
1.Messenger RNA is made from DNA by an enzyme (RNA polymerase).
2.A small section of DNA unzips, revealing the actual message (called the sense strand) and the template (the anti-sense strand).
3.A copy is made of the gene of interest only, producing a relatively short RNA segment.
4.The knots and kinks in the DNA provide crucial topological stop-and-go signals for the enzymes.
5.After messenger RNA is made, the DNA duplex is zipped back up.
Adding to the complexity and sophistication of design, the genetic code is read in blocks of three bases (out of the four possible bases mentioned earlier) that are non-overlapping.
Moreover, the triplicate code used is "degenerate," meaning that multiple combinations can often code for the same amino acid-this provides a built-in error correction mechanism. (One can't help but contrast the sophistication involved with the far simpler read/write processes used in modern computers.)
A Common Software House
All living things use DNA and RNA to build life from four simple bases. The process described above is common to all creatures from simple bacteria all the way to humans.
Evolutionists point to this as evidence for their theory-but the new discoveries of the complexity of the process, and the fact that bacterial ribosomes are so similar to those in humans, is strong evidence against evolution. The complexities of cell replication must have been present at the beginning of life.
A simple explanation for the similarities of the basic building blocks can be found if one realizes that all life originates from a single "software house." He is awesome indeed!
[Ed Note: Dr. Jerry Bergman is a professor of science at Northwest College, Archibold (Ohio) and is working on his third Ph.D. in molecular biology. He also has degrees in biology, psychology, and evaluation and research.]