Radio commentator Paul Harvey (1918-2009) was famous for his “The Rest of the Story” segments. Sometimes people perceive an air of knowledge with clever emphasis on the introductory point in their discussion. We have referred to the well-known expression “It’s in our
DNA.” Yes, there’s a basic glossary definition of DNA, the starting point in any discussion of genetic inheritance. But the sequel, the rest of the story, awaits discovery.
At a simple level,
DNA could be described as a lengthy linear assemblage of common elements--simple atoms and molecules in virtually every body cell. This reductionist explanation is technically accurate. All physical and behavioral traits of the human body could be understood in terms of atoms of carbon, hydrogen, oxygen, nitrogen, and phosphorus, and the molecules they form. However, this account does not even come close to an explanation. The sequel to the story is a topic of majestic wonder.
We note that
DNA is a nucleic acid. The DNA molecule is a macromolecule. It is composed of smaller molecular assemblages called nucleotides. Many nucleotides link together to build the polynucleotide we know as DNA. There are four types of nucleotides in DNA. They are adenine, thymine, guanine, and cytosine, abbreviated A, T, G, and C for short. These nucleotides always pair together: A with T, and C with G. Chemically, the nucleotides are bases. They are called, therefore, base pairs. AT or CG link together the two side rails of the double helix. These AT or CG pairs form “rungs” on the helix ladder, and occur in an infinite variety of sequences. The sequences may be compared with a digital code. We illustrate a two character digital code: 001101000111. Unlimited sequences of digits are possible either in our numeral example or in DNA base pairs.
As children we may have been fascinated by games using secret codes. The secret to “winning” was figuring out how to translate the meaning of the code. If we had the secret de-coder, we knew the location of a “treasure” we could not otherwise discover. The code, formerly a series of nonsense letters or symbols, became meaningful.
The base pairs of
DNA macromolecules for each human are arranged in 3.2 billion “digits,” with an unlimited sequence of combinational possibilities. Bio-scientists have broken the code in the past 60 years. The code stores all genetic information for the individual, enables him or her to duplicate that information, and pass it along to the next generation. Ultimately the code provides information to build raw materials for thousands of different types of body tissues (proteins), and enables the body to assemble the materials in the correct way. This miracle occurs each time a new baby is conceived and born.
DNA in the human genome provides the template for the materials of which our bodies are built. Coding DNA provides instructions for manufacturing and assembling many thousands of different proteins, the raw materials for building body tissue. Proteins are composed of twenty different amino acids. Non-coding DNA is also present in the human genome. Coding DNA is arguably the most interesting.
The majority of
DNA in our bodies is the “non-coding” variety. Formerly, it was termed junk DNA because bio-scientists did not know its function. As time goes on, we know more of its function and more of the secrets of life God has authored at the level of the cell. The government supported ENCODE project, a product of the NHGRI (National Human Genome Research Institute), discovered that 80% of non-coding DNA has control and regulatory function within the cell. This trajectory of accumulated knowledge contrasts with biologists’ former belief that there was a large amount of DNA which served no function and was considered an evolutionary “left-over.” Almost all findings of molecular biology have become known in the lifetime of the grandparents of our high school and college students.
Let’s recall the traditional values communicated by Paul Harvey. Were
to remark that “It’s in the Harvey DNA,” he may have expanded on the topic in his segment “The Rest of the Story.” The knowledge of DNA goes far beyond the introductory knowledge columnists and commentators provide. When the rest of the story is broadcast, we may understand that the ongoing discoveries in molecular biology point ever more clearly to the work of our Almighty God.
Our future posts will cover other small segments of “The Rest of the Story.”