A Dane County Almanac
And Other Short Stories
“Bill's Primer on the Genome”
A book review of the “Genome”
“The fuel on which science runs is ignorance. Science is like a hungry furnace that must be fed logs from the forests of ignorance that surrounds us. In the process, the clearing we call knowledge expands and the longer its perimeter and the more ignorance comes into view.”
Since Matt Ridley wrote the above in his book, “Genome – The Autobiography of a Species in 23 Chapters,” scientists have devoured gigantic forests of ignorance in mapping the DNA structure of human life. The clearing that this knowledge has produced is greater than any other single scientific breakthrough in human history.
This being the case, it is not surprising that in my journey to more clearly discover my own vision, Ridley’s book is brought into my living room. I recently wrote about reading Brian Swimme’s book, “The Universe Story.” These new scientific cosmologies literally broaden my context and orientation many thousand times over. If you would have asked me just last week whether I would ever discover anything comparable I would have said certainly not. Certainly if one is talking about the macro world, perhaps this would still be my answer. Little did I know that going inward into the micro field of genetics I would find an equal if not even greater discovery?
Soon after settling into the Ridley’s Genome I hesitated. With my limited scientific background, particularly in the biological sciences, will I really be able
journey deep, deep down into the human cell. Could this science journalist write to bring this new micrometer world into my awareness? Just when I was beginning to complain to myself that the author should have included a “gene primer” at the outset, there it was. Incidentally I should note here that I learned later in this book that I may have a gene which serves to motivate me whenever I am puzzled, uncertain or confused. If this is really so, it clearly kicked in when the primer appeared.
From this brief little primer I learned that the human body contains 100 trillion cells. The size of each cell is less than a tenth of a millimeter (or a pin point) across. Inside each of our white cells is a black blob called a nucleus? Inside each nucleus are two complete sets of the human genome. Each genome set contains 30,000 to 80,000 genes on the same twenty-three chromosomes. Before the discovery of the genome we did not know there was a document at the heart of every cell three billion letters long of whose contents we knew nothing.
What came next seemed almost too good to be true. I learned that the author will use a book as a metaphor to explain all I will need to know in order to understand his entire book. Immediately I remembered some early advice that my father gave me when I was less than ten years old.
He said, “Bill. If you really want to get an education or become a scholar, all you really need to know is how to read. Once you learn to read, you will be able to learn anything there is to learn.” These words acted to motivate me to want to read everything the author had to say about the human gene.
In the author’s book metaphor there are twenty-three “chapters,” for the twenty-three human chromosomes. Each chapter contains several thousand “stories” called genes. Each story or gene is made up of “paragraphs,” called exons, which area interpreted by “advertisements” called introns. Each paragraph is made up of “words” called codons. Each word is written in “letters” called bases. The Gerome book is written with only three letter words, and using only four letters: A, C, G, T. DNA is a chemical and RNA is also a chemical. Genetics is really just this simple! Before the discovery of the genome, we did not know there was a document at the heart of every cell three billion letters long of whose contents we knew nothing.
Continuing to use the book metaphor, I learn that this “book” can photocopy (or replicate) and read itself. A single strand of DNA can copy itself. The code is written not on paper but on long chains of sugar and phosphate called DNA molecules. There are one million codons (words) in the human genome. Everything in the body is made from protein. Every protein is a gene. The body’s chemical reactions are catalyzed by proteins known as enzymes. I learned that when genes are replicated mistakes are sometimes made or a mutation occurs. There are 64 different codons or words and many of these words the same meaning.
With the genome there are 4,000 million years of earth history and five million species. One of these five million species is a conscious human being. Consider also for a moment, that among the 6 thousand million people that has been on the planet, you and I were privileged enough to be born in the country where the “word” (DNA structure) was discovered. It was during our short lifetime that the greatest, simplest, and most surprising secret in the universe was discovered. Our DNA is a recipe or instructions on how to replicate me and you. It’s a message written in a code of chemicals – one chemical for each letter. Chromosomes are large molecules designed to carry our heredity.
DNA are not merely structurally important but functionally active substances in determining the biochemical activities and specific characteristics of cells, and that by a means known as chemical substance it is possible to induce predictable and hereditary changes in cells. Life, to a rough approximation, consists of three atoms - hydrogen, carbon and oxygen. They make up 98% of all atoms in living beings.
Finally, and this will be the end my genetic understanding to date, I want to distinguish between two chemicals, protein and DNA. A protein consists of chemistry, living, breathing, metabolism and behavior. It is what biologists call the phenotype. DNA consists of information, replication breeding, and sex, and is what biologists call the genotype.
Does the existence of the Genome now mean that it will be only a few years before scientists create a genetically modified human being? After all we already have a cloned sheep. Is our genetic make-up the primary determinant of our free will as humans?
The author of Genome puts it this way. “The crude distinction between genes as implacable programmers of a Calvinists predestination and the environment as the home of liberal free will is a fallacy.” Ridley argues that if genes can affect behavior and behavior can affect genes, then the causality is clearly circular and not single-dimensional.
Paradoxically, our genes, because they are unique to each of us, are perhaps our greatest protection against the many determining threats that face us daily. These many wide and varied determinate conditions include both genetic and environmental. We have the most to fear from the latter and it is the most pervasive.
Again, Ridley says it best. “Freedom lies in expressing your own determinism, not somebody else’s. It is not the determinism that makes the difference, but the ownership. If freedom is what we prefer, then it is preferable to be determined by forces that originate in ourselves and not in others. Part of our own revulsion at cloning originates in the fear that what is uniquely ours could be shared by another. The single-minded obsession of the genes to do the determining in their own bodies is our strongest bulwark against loss of freedom to external causes.
We know that there is no single gene for free will in the genome. Rather there is something infinitely more uplifting and magnificent: a whole human nature, flexibly preordained in our chromosomes and idiosyncratic to each of us. Everybody has a unique and different nature.
