Today’s New Reason To Believe

Posted by Fazale ‘Fuz’ Rana, Ph.D.

DNA Optimized for Photostability, Adds to the Evidence for Design

About ten years ago my family and I moved from Ohio to sunny Southern California. I don’t think I could ever go back. I have no desire to experience ever again the frigid winters and humid summers that are major parts of living in the Midwest.

The year-round beautiful weather in the “southland” makes it possible to enjoy many carefree hours outdoors. But it also prompts some concerns about spending too much time in the sun. Soaking up too many of the Sun’s harmful rays can cause long-term damage to the skin—unless, of course, one lathers on the sunscreen.

Like Southern Californian sun “worshippers,” DNA also faces problems with short wavelength UV-radiation from the sun. This radiation can damage this all-important biomolecule. Fortunately, biochemists have discovered that DNA has unusual photostability. Scientists believe that specific structural features of DNA make it resistant to the harmful effects of the sun. It’s as if DNA has its own built-in sunscreen.

New research has uncovered some of the specific aspects of DNA structure that contribute to its unusual photostability, and—with this insight—add to the weight of evidence that biochemical systems are the work of a Creator.

The Structure of DNA

DNA consists of chain-like molecules known as polynucleotides. Two polynucleotide chains align in an antiparallel fashion to form a DNA molecule. (The two strands are arranged parallel to one another with the starting point of one strand in the polynucleotide duplex located next to the ending point of the other strand and vice versa.) The paired polynucleotide chains twist around each other to form the well-known DNA double helix. The cell’s machinery forms polynucleotide chains by linking together four different subunit molecules called nucleotides. The nucleotides used to build DNA chains are adenosine, guanosine, cytidine, and thymidine, famously abbreviated A, G, C, and T, respectively.

The nucleotide molecules that make up the strands of DNA are, in turn, complex molecules consisting of both a phosphate moiety, and a nucleobase (either adenine, guanine, cytosine, or thymine) joined to a 5-carbon sugar (deoxyribose).

Repeatedly linking the phosphate group of one nucleotide to the deoxyribose unit of another nucleotide forms the backbone of the DNA strand. The nucleobases extend as side chains from the backbone of the DNA molecule and serve as interaction points when the two DNA strands align and twist to form the double helix.

When the two DNA strands align, the adenosine (A) side chains of one strand always pair with thymidine (T) side chains from the other strand. Likewise, the guanosine (G) side chains from one DNA strand always pair with cytidine (C) side chains from the other strand.

The Photostability of DNA

As I pointed out in chapter seven of The Cell’s Design, biochemists have known for a while that the particular nucleobases found in DNA display ideal photophysical properties. Even though DNA routinely experiences photophysical damage, it could be far worse. It turns out that the optical properties of the bases found in nature minimize UV-induced damage. These nucleobases maximally absorb UV-radiation at the same wavelengths that are most effectively shielded by ozone. Moreover, the chemical structures of the nucleobases of DNA allow the UV-radiation to be efficiently radiated away after it has been absorbed, restricting the opportunity for damage.

To gain further insight into the structural features of DNA that contribute to its photostability, researchers from Germany prepared a number of model DNA compounds. It turns out that the molecular interactions that promote the pairing of the side groups in the DNA duplex help dissipate absorbed light energy. Variation of the nucleotide sequences in the strands of DNA also plays a role in photostability. This variability prevents long-lived excited states from forming when UV-radiation is absorbed by DNA.

It appears that DNA has been designed to have optimal photostability. This property is critical for DNA’s role in the cell as a data storage system. DNA harbors the information needed for the cell’s machinery to make proteins. It also houses the genetic information passed on to subsequent generations. If DNA isn’t stable, then the information it harbors will become distorted or lost. This will have disastrous consequences for the cell’s day-to-day operations and make long-term survival of life impossible.

As I discuss in The Cell’s Design, photostability is not the only feature of DNA that has been optimized. Other chemical and biochemical features appear to be carefully chosen to ensure its stability; again, a necessary property for a molecule that harbors the genetic information.

Optimized biochemical systems comprise evidence for biochemical intelligent design. Optimization of an engineered system doesn’t just happen—it results from engineers carefully optimizing their designs. It requires forethought, planning, and careful attention to detail. In the same way, the optimized features of DNA logically point to the work of a Divine engineer. It appears as if someone carefully designed the structure of DNA to spend many long hours in the sun.

by Jeff Zweerink

Imagine a luxurious house on a remote ranch. Looking out the windows you see majestic mountains on one side and a scenic ocean expanse out the other. The location insures that you can enjoy the awe-inspiring scenery without disruptions. Such imagery corresponds to the solar system’s location in the Milky Way Galaxy (MWG). In fact, some scientists have argued that Earth’s idyllic habitat in the MWG reflects the work of a Designer who fashioned Earth with the explicit intent of humanity discovering his handiwork displayed throughout the universe.

Regardless, the solar system did not start out in such prime real estate. As discussed in a previous TNRTB, a chaotic and violent cluster of stars birthed our home. According to this scenario, a number of supernovae occurred in the cluster during the time period when the solar system formed. After formation, the Sun and all its planets were ejected from the dense cluster of stars before any interactions with adjacent stars disrupted the orderly orbits that now characterize Earth and the rest of the planets.

New research confirms that one of these supernovae in the dense star cluster probably triggered the formation of the solar system while simultaneously seeding it with an abundance of elements heavier than helium. This seeding enhances the concentration of radioactive isotopes incorporated into Earth so that it sustains life-critical plate tectonic activity for billions of years. While astronomers believed that supernovae could trigger star formation and simultaneous seeding, they had not been able to model the process on a computer using realistic conditions.

Early computer models of the process assumed a constant temperature for the supernova shock wave and the solar nebula. In reality, the collision of the shock wave with the nebula will cool the shock and heat the nebula. As described in an The Astrophysical Journal article, advances in computer modeling remedied this deficiency. However, in order for the nebula to remain sufficiently cool so that it collapses, it must contain an abundance of water and carbon dioxide. Consequently, before a life-sustaining solar system can form, at least one or two generations of stars must live and die in order for adequate quantities of carbon and oxygen (essential components of water and carbon dioxide) to exist.

This research provides further evidence that life arose in the universe as soon as the universe could support it. Such timing comports well with the idea that a supernatural Creator fashioned the universe with the purpose of creating life—particularly human life.

Kenneth Richard Samples

As a speaker at a theological conference I was asked the following provocative question:

How is it possible for Christ to have suffered the eternal wrath of God in just several hours on the cross when human recipients of God’s judgment suffer for all eternity?

The crux (Latin for “cross,” English for “central point”) of this question relates to how Jesus’ suffering and death accomplished an eternal result in a short temporal period of time.

I propose that the answer to this perplexing question is found in the historic Christian view of the person of Jesus Christ as the divine Logos or Son.

Jesus Christ is an eternal personal being.

Jesus is fully human, but not solely human. He is also fully divine. The orthodox view of Christ is that he is a single person with two natures, one divine and one human. Ancient Christians referred to Jesus as the theanthropos (Greek: the God-man).

So, while Jesus has both a divine and a human consciousness (corresponding to divine and human natures and divine and human wills), he is ultimately one person; and that one person is the divine Logos. His human consciousness is found in hypostatic (or personal) union with the divine. Jesus’ human consciousness, therefore, has no existence of its own (impersonal) apart from its union with the divine in the Incarnation. Orthodox Christian theologians refer to this as the enhypostasis and anhypostasis of Christ (see here).

Christ possesses a fully human nature, but the self-conscious ‘I’ is the eternal Logos or Son. He is therefore an eternal person, the second person of the divine Trinity. In a philosophical sense, Jesus is two Whats and one Who. (In other words, he possesses two distinct natures, one divine and one human, but is, nonetheless, a single person.)

How does all this impact the original question?

How is it possible for Christ to have suffered the eternal wrath of God in just several hours on the cross?

Christ could suffer the eternal divine wrath during his temporal suffering on the cross because he is an eternal personal being. The eternal person accomplished an eternal sacrifice. An eternal personal being can offer an eternal sacrifice by the very nature of his being, without consideration to time limitations.

The point is not how long Christ suffered on the cross for sins, but who the person was that offered the sacrifice. It is the dignity, grandeur, and holiness of Jesus Christ’s eternal personal being that extinguished the eternal wrath of God.

1 Peter 1:18-19 notes:

For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your forefathers, but with the precious blood of Christ, a lamb without blemish or defect.

An eternal sacrifice was needed to appease God’s eternal wrath against sin but no mere human and temporal person could achieve it. Thus the eternal Christ, the one and only God-man, offered an eternal sacrifice that achieved redemption for all who believe the Gospel (John 3:16).

For more on the study of Christ’s person, nature, and work, see chapters 9 and 11 of my book Without a Doubt: Answering the 20 Toughest Faith Questions and chapter 8 of my book A World of Difference: Putting Christian Truth-Claims to the Worldview Test.