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This article was originally published as a chapter in the book “Design and Catastrophe: 51 Scientists Explore Evidence in Nature"
When I was a kid, my interest in natural sciences was stirred to life when my science teacher said that “molecules are moving.” From then on, my motivation was to understand how God’s intelligent designs work in nature. I ended up pursuing science and working on DNA.
Deoxyribonucleic acid, commonly known as DNA, is a tiny molecule with a diameter of 1.8 to 2.3 nm and a pitch of 3.4 nm. To have an idea of how small DNA is, consider that one nanometer is onebillionth of a meter. More than 10,000 DNA strands could fit in the width of a human hair. DNA is located inside the nucleus of the cell and consists of two chains that twist around each other like a winding ladder, stabilized by the highly specific pairing of molecules called “base pairs.” There are 10–12 base pairs per helical turn.[1]
The DNA structure is kept together by two hydrogen bonds between adenine (A) and thymine (T) and three hydrogen bonds between cytosine (C) and guanine (G). It has pentose deoxyribose sugar and a phosphate backbone joined by covalent bonds, which make the molecule stable.
The DNA inside each of our cells is too small to be seen with the naked eye. However, if straightened out, the total DNA in a human cell would stretch to about 1.5–3.0 m.[2] Since the human genome (the totality of an organism’s hereditary information) contains around three billion base pairs of DNA in 46 chromosomes in about 1013 cells of the body, the total length of DNA present in an adult human being is about 2×1013 m,[3] long enough to wrap around the earth 500,000 times. Thus, DNA is considered one of the most extended molecules on Earth. In spite of this very long configuration, it is well designed to fit inside the nucleus of a cell without distorting the encoded information. It has a stunning coiling ability too. The folded and packed DNA molecule is approximately 10,000 times shorter than its linear form.[4] Even though this nanomolecule is tightly packed, it can quickly unpack when the right signal is recognized by the cell. Remarkably, the uncoiling of DNA requires accurate sequential actions of topoisomerases to unpack the DNA supercoils.
Approximately 99.5% of DNA is similar in all humans, but the way it functions can vary greatly.[5] In other words, although we all have almost similar DNA make-up, if these DNA sequences are differentially processed from each other, we end up having different faces, complexions, hair patterns, and eye colors. This makes each person phenotypically and genotypically unique. The uniqueness of the DNA sequence between and among species is utilized in fingerprinting individuals with a high degree of accuracy.
The processing of DNA occurs in an intricate step-by-step fashion. The parent DNA is replicated, and the information is copied to a molecule known as messenger RNA (mRNA) inside the nucleus of the cell. When the RNA is mature (after the addition of 5' methylated guanine cap and adenosine residues at the 3' end), mRNA leaves the nucleus and goes out into the cytoplasm of the cell, and here mRNA is translated to protein by the aid of the ribosomes and several enzymes. The generated protein is then further modified to perform specific tasks inside the cell, following a very orderly and precise method. A system has been provided to correct replication errors along the way. In some instances where an incorrect base is added, an enzyme, DNA polymerase, proofreads the base that has just been added and correspondingly corrects and replaces it with the correct nucleotide base. Where some errors are not corrected during replication, mismatch repair enzymes recognize the incorrectly added nucleotide, excise it, and then replace it with the correct one. These intricate delivery systems and the extraordinary degree of timing and accuracy of these processes are hallmarks of intelligent design.
The astounding properties of this biopolymer captivated the minds of scientists and bioengineers. Using the DNA origami approach, one can envision and create any design in the laboratory.[6] DNA could be used to construct and organize nanoscale gold rods into larger structures.[7] It can also be used to fuel molecular machines.[8] When two complementary strands of DNA combine, about 70 MeV of free energy is released as each base pair is formed.[9] This energy is enough to power a nanoscale device. The above nanotechnological advancements along with DNA 3D structure, DNA tweezer, supramolecular DNA assembly, and creation of new DNA motifs are anchored on DNA’s complexity, aperiodicity, and ease of self-assembly, which could revolutionize molecular-scale electronics and nanomedicine.[10]
Interestingly, DNA is also a superior storage material of information. It stores specific instructions on the myriad processes of life. DNA can hold an enormous amount of information compared to the current data storage capacity of computer hard drives. Because of the immense capacity of DNA to store information, it is now recognized as the storage medium with the highest known information density.[11] The sophisticated design of this nanomolecule makes it suitable to store the instructions for all life.
This magnificent nanomolecule inside a tiny cell is a natural wonder in which God’s instruction manual and the blueprint of life of all living creatures reside. In particular, the synchronous processes during DNA replication, transcription, and translation orchestrated by myriad biomolecules in a fraction of a second with unprecedented timing and accuracy testify to intelligent design. The intricate design of DNA, its stability, flexibility, ability to store information, and associated orderly processes point to the great and intelligent Designer who created all things in the vast universe.
NOTES
[1]K Mizoguchi, H Sakamoto. DNA engineering: properties and applications. Singapore: Pan Stanford; 2017, p. 349.
[2] S Chen. Length of a human DNA molecule. In: G Elert, editor. The physics factbook, 2006. Available from: http:/hypertextbook.com/ facts/1998/StevenChen.shtml [accessed June 24, 2020].
[3] Ibid.
[4] Ibid.
[5] S Levy, G Sutton, PC Ng, L Feuk, AL Halpern, BP Walenz, N Axelrod, J Huang, EF Kirkness, G Denisov, et al. The diploid genome sequence of an individual human. PLoS Biology 2007; 5(10):e254.
[6] A Turberfield. DNA as an engineering material. Physics World 2003; 16(3):43.
[7]. NC Seeman, HF Sleiman. DNA nanotechnology. Nature Reviews Materials 2017; 3(1):17068.
[8] Ibid.
[9] Ibid.
[10] Turberfield, op. cit.
[11] J Bohannon. DNA: The ultimate hard drive. Science 2012 (Aug. 16). Available from: https://www.sciencemag.org/news/2012/08/dna-ultimatehard-drive [accessed June 24, 2020].
Orlex B. Yllano is the current chair of the biology department at the Adventist University of the Philippines. He finished his PhD in Molecular Biology and Biotechnology at the University of the Philippines, Los Baños. Currently, he is the president of the Philippine Society of Biochemistry and Molecular Biology, South Luzon chapter. He has published papers on conservation genetics, crop biotechnology, and phytoremediation.