Genetic motives and motivations
Writing about things that I care about provides enjoyment, satisfaction, and a degree of comfort similar to that which the consumption of chocolate provides to others. Today was a difficult day, for reasons that I cannot determine and so, for the pleasure of it, I return to one of my favorite topics, one which I have discussed here before, the perpetuation of the species and the transmission of genetic material. My desire to write about genes may also have been influenced by a fascinating paper I read recently in which scientists described a new technique which allows for the visualization of bundles of DNA fibers using the methods of traditional transmission electron microscopy. The last time I mentioned DNA here it was in reference to the seeds of the milkweed plant. This time my story begins with a walk that Joanna and her good friend, Ann, enjoyed the other day. When she returned I asked Did you see any nature? She was excited to tell me about masses of frog spawn she had seen; a sure sign of spring. A few days later we took our bike along the same stretch of trail and came across a group of folks from the Department of Natural Resources and from a local fire department. The combined forces had just completed a controlled burn parallel to and just off the walking path. For days Joanna worried about the fate of the eggs. She fretted, not only because of the fire but also because the egg masses had been deposited in a small depression which ran along side the trail and her concern was that the water might have dried in the intervening days which had not seen much rain. This past weekend we had the bike out once more and stopped to observe the spawn. All was well. The encapsulated embryos were housed as part of jellied, buoyant, masses and glints of sunlight danced across their surfaces. The embryos were of such interest that I decided to post this trio of images. Each embryo floated, in its tiny, protective, capsule. Quiet, save the periodic paroxysms which moved it about its watery abode. Each embryo grew under the influence of DNA molecules deep within each of its cells. How strange, as if the entire scenario were taken from a script of some Sci-Fi movie. Eventually the embryos would complete organogenesis, hatch as tadpoles, and then undergo metamorphosis to the adult stage which is perhaps more familiar to us. It is a fascination to contemplate the motive forces which drive these processes and the motivation for them. My best explanation of the former relies on the laws of thermodynamics. In the same way that, having attained the top of that very first hill, a roller coaster car transforms the energy of potential into the energy of movement, chemicals too interact and thereby achieve low energy states. The DNAs, the RNAs, the polymerases, the helicases, and the topoisomerases all interact in ways which eventuate as a collection of proteins we call frog tissue. In other words, organogenesis and development are, in my view, fortuitous side-consequences of the entropic interplay between and among abiotic (nonliving) molecules. And, it’s totally, entirely, and absolutely without conscious motivation or foresight. For who could assign motive to interacting chemicals anyway? Chemical moieties react with chemical moieties because the laws of thermodynamics dictate they will. What a weird and wonderful thing it is to view a frog as a not-so-simple side consequence of DNAs competing, thermodynamically-speaking, in a world of other DNAs, and doing so because they can. As for motivation? There isn’t any. How could there be? Isn’t it grand?