Lately, I’ve been asking myself a few pretty basic questions: What on earth is a gene? And, an even bigger question: What on earth is evolution?
In 1953, molecular biologists James Watson and Charles Crick claimed to have unlocked the “secret of life” by unraveling deoxyribonucleic acid (DNA), the genetic coding in the nucleus of every cell. Thereafter, scientists came to believe that within the coiled double helix lay every individual’s lifelong blueprint.
This theory promotes DNA as the Renaissance man of the human body – architect, master builder and central engine room – whose tool for all this amazing activity is a handful of the chemicals that make proteins.
The modern scientific view is that DNA somehow manages to build the body and spearhead all its dynamic activities through a straightforwardly mechanistic process of selectively turning on and off certain genes — the steps on the spiral ladder of the double helix.
These nucleotides make copies of themselves as messenger ribonucleic acid (RNA) molecules, then use this blueprint to choose from an alphabet of amino acids the genetic ‘words’ that create one of the body’s approximately 150,000 specific proteins, which are responsible for the body’s myriad functions.
From the outset, Watson and Crick laid down a set of mechanistic rules they termed the “central dogma” of microbiology, which maintained that cellular informational commands flowed in a single direction, from DNA to RNA to a selected combination of amino acids to the assemblage of proteins.
Until recently, scientists maintained that gene activity is a hermetic process and DNA the central and only dictator.
In fact the latest evidence suggests that information flow between DNA and both inside and outside the body is highly dynamic — as geneticist John Cairns of Harvard’s School of Public Health learned in the mid-1980s. Cairns carried out an experiment that would set off one of the largest arguments in modern biology.
He’d selected bacteria with a genetic defect rendering them unable to digest lactose, the sugar present in milk, then introduced them into a batch of Petri dishes containing cultures whose only food-source was lactose. Without any digestible food, the bacteria faced death by slow starvation.
According to orthodox science, the bacteria would not be able to colonize; without a food source to drive metabolic processes, they could not carry out normal reproduction. Nevertheless, in every Petri dish, Cairns found a goodly number of thriving colonies.
When Cairns tested for genetic changes in his colonies, he found that a single type of gene had changed – those preventing for lactose metabolism. Identical changes in just those genes had occurred within every new colony in every Petri dish.
Through some unknown mechanism, the bacteria had activated life-saving mutations in direct response to an extreme environmental crisis, and these mutations had saved their lives.
Somehow the extreme environmental conditions had caused changes in genes, enabling the bacteria to digest the only food available to them.
The bacteria had evolved purposefully, not randomly, in order to restore balance and harmony with their environment.
In 1988, Cairns published his findings in the prestigious journal Nature under the droll title ‘The Origin of Mutants,’ an irreverent nod to Charles Darwin.
Darwin had proposed that the evolution of species occurs randomly through copying errors in inherited characteristics, but that only those changes most conducive to survival prevailed.
Cairns instead proposed that cells within organisms have the ability to orchestrate their own ‘directed mutation,’ rapidly adapting to a changing environment.
American journal Science dismissed Cairns’ work as tantamount to heresy, and it took ten years for the first popular science publication to introduce his material to the public.
As other researchers looked closer, they discovered that Cairns was right. Under environmental stress, a special enzyme in a bacterium cell gets activated, initiating a fevered copying process of cell DNA with a deliberate array of random mistakes like a photocopier run amuck — a mechanism now referred to as ‘somatic hypermutation.’
If any one of these mutated genes happens to be able to assemble a protein with the key to overcoming the environmental problem, the unthinkable occurs: the bacterium excises and jettisons the original problem gene from its DNA, and then replaces it with the new gene.
This is the likely process by which bacteria manage to outwit antibiotics.
Restructuring your genes
Other scientists after Cairns have begun to show that the environment is constantly changing an organism, not simply through epigenetics – the study of factors above the gene that turn it on or off — but directly by changing genes.
They’ve discovered a host of biochemical systems that restructure DNA. The information flow to and from DNA is interactive, occurring in two directions from other parts of the body and even from the outside.
James Shapiro, a professor in the Department of Biochemistry and Molecular Biology at the University of Chicago, studies the means by which organisms can actively restructure their own genetic information.
Genes change, says Shapiro, as a consequent of ‘natural genetic engineering,’ not from accidents — but a constant dynamic process of adaptation between an organism and its environment.
‘Today we know that biological molecules change their structures as they interact with other molecules,’ he says, ‘and these structural changes contain information about the external environment and conditions within the cells.’
Shapiro likes to refer to the genome as a ‘read-write memory system,’ rather than blueprint, that gets modified by a host of influences – internal and external.
All of this suggests something enormous. Modern evolutionary synthesis emphasizes that your future is a genetic crap shoot — a case of good or bad genes.
Presently we are discovering that the natural world is created as a dynamic, symbiotic partnership, and evolutionary change, in a sense, is prompted by a joint solution, restoring balance and harmony when an organism is out of alignment with its environment.
So the big question is not simply how we humans are going to amend the havoc we’ve wreaked upon the earth.
The question is how are all these planetary crises of late — global warming, increased natural disasters and ecological crises — going to adapt us so that we may continue to live here and at last in harmony with all these changed surroundings?