dr-iPod

Podblack

As I walked pasture the other day I came across this empty Milkweed seed pod. In one way the empty receptacle speaks to the end of life and to decay. In another way however, and in dramatic contrast, this view foreshadows the inevitability of the seasons, the coming of spring and renewal; for surely the vegetable diaspora will respond to changes in day length, to the warming of the soil, germinate and grow. Until then however many seeds, especially those produced by plants living in temperate latitudes, need to experience a prolonged period of cold before they are able to germinate. This is called vernalization and is nature’s way of ensuring that seeds set in the fall do not germinate until spring. Such a sensible strategy, so elegant. But, allow me to back up to give seeds proper consideration; for, what is a seed? Is it an encapsulated, nutrient fortified, embryo. And what is an embryo? An embryo is encapsulated DNA. And what is DNA such that its expression leads to the production of embryos and individuals? The popular understanding is that DNA is the blueprint of life. To be sure, but that simply begs the question. How does DNA work? A detailed consideration of information flow from gene to protein is beyond the scope of this humble farm blog but perhaps, at the risk of having you pass quickly to the next post in your reader, you will pause long enough for a few of the essentials?

James Watson, Francis Crick, and Rosalind Franklin are well-known for having worked out the structure of deoxyribonucleic acid and Watson, Crick, and Maurice Wilkins shared the 1962 Nobel Prize in Physiology or Medicine for their work. Franklin died in 1958 and was therefore ineligible for nomination to the prize and has only recently been fully recognized as having contributed in significant and crucial ways to what may have been the most important scientific discovery of the twentieth century. If you look at the schematic below you can see that sugar (pentagons) and phosphate (in yellow) form the backbone of the DNA double-helix, the handrails of the ladder in the classic pedagogical analogy. Nitrogen-containing moieties are arranged in the middle of the molecule in repeated pairs, the rungs, Adenine/Thymine and Guanine/Cytosine. Now, here’s the really fascinating bit, the genetic code of life may be found in the specific sequence of base pairs. That’s it? … you say? Yup … it’s that easy … and differences in base sequences are responsible for the differences between Leonardo, Copernicus, Einstein, Newton, and you and me. These sequences code for amino acids which come together to form proteins. Sperm and egg are each comprised of 23 chromosomes which make up the Human Genome which has been estimated to be made up of over 3 billion base pairs. Although egg and sperm represent parental contributions to offspring consider that the real business of reproduction is the act of passing coded DNA messages between the generations. Genes aren’t legs, arms, and spleens … genes don’t confer bodies, as such. Genes represent coded information, information that may be expressed as flamingos, or elephants, or elm trees, or squid … generation after generation, across the millennia, and over millions upon billions of years. Bodies don’t do time travel but information does. The next time you see the tufted seed of a milkweed floating along with the breeze realize that what you are really seeing is encapsulated information, information which guarantees the perpetuation of genes contained within the plants which produced the seed itself. Perhaps it might give you something of different spin on life to consider that some would view our human bodies as simply a gene’s way of making another gene. In the text of The Selfish Gene author Richard Dawkins wrote … When we have served our purpose we are cast aside. But genes are denizens of geological time: genes are forever. Some would say that we live in an age of information. The truth of the matter is that the age of information has been around as long as life itself. When we do away with all the fluff, what remains are the capacities of all sorts of genes to make copies of themselves … and the diversity of life represents a myriad ways of doing this. And then of course there is the metaphysical question of why genes bother to perpetuate themselves at all. And the answer to that question seems to be that they do so because they can. And the nature of that reality is a fruitful topic of conversation for another day.

15 thoughts on “dr-iPod

  1. Catchy title! Never knew about a woman’s contribution to DNA science! Your blog brought back images of college biochemistry … my favorite subject. I actually tutored kids and remember knowing ALL the aspects of the Kreb’s cycle! Thanks for reminding us how important the humble seed pod is! :)

  2. Your statement that “Chunks of oak don’t flow like shells or ears….” threw me for a bit, but then I realized you meant ears of grain. Context, context, context.

    Like you, I’m fond of milkweed pods. Have you thought of altering the photograph to make the background completely black, so the abstracted pod “glows in the dark”?

    • Good morning Steve. Your comment gave both Joanna and me a very good laugh indeed! She is my ‘in house’ editor and even she didn’t pick up on the potential for confusion here! The mental image of shells and ears flowing is something from the mental recesses of very Salvador Dali – wouldn’t you say? Perhaps I should read these things more closely and with an eye toward this. I’ll see about that pod-modification. Have a great, warm, day … we’ve got freezing rain at the moment and my morning ritual of the coffee run to town was a bit slippery. D

  3. This black and white photo of the “empty” seed pod is very apt. I like empty pods – for some plants the withered pods are more beautiful (… in the eye of the beholder…) than the blossoms. As you mention Dawkins’ “Selfish Gene” … this is the chance to ask a specific question: I have come across several articles/books recently that claim that these ideas are actually due to Robert Trivers (http://insidetheblackbox.tumblr.com/post/19797229408/robert-trivers-and-the-history-of-self-deception). According to this article Dawkins hasn’t denied this. This is probably one of these pointless discussions about “fame” (as discussed on M.’s blog) – but I am still curious what the community of experts in evolutionary biology thinks about “ownership”.

    • You bring up an interesting point. Both Dawkins and S.J. Gould are well known for having brought evolutionary science to the masses, and for that they should be applauded. Both certainly published their own works in the primary (peer-reviewed) literature but both also wrote secondary essays that relied heavily on the work of others. If you read any of a number of essays by either author they are always careful to give credit when appropriate. I once listened to a lecture in which Dawkins suggested Gould relied entirely on the work of others (which, of course, isn’t true) when all the while Dawkins himself was relying heavily on what came before. Anyway, Trivers work on altruism was certainly ground-breaking, when it was first published, and very interesting. As to whom the idea of ‘selfish’ genes is originally attributable … I am not sure … it may well be Trivers. I believe that lots of folks, even before Trivers, probably recognized that the gene could perhaps be a unit of selection … but whether anyone before Trivers assigned motivation to them I do not know. D

      • Thanks, Dave! So it seems to be that old discussion of “the lonely genius” (which is probably an illusion) and the “synthesizing communicator”. In “Einstein’s anniversary years”, 2005, there were lots of accounts of Einstein being one or the other. I read Thomas Kuhn’s landmark book on the infamous paradigm shift last year – and he gave some interesting examples (from physical chemistry mainly) why it is actually impossible to really state “who was first” – e.g. because the original discoverer (I think it was: discoverer of oxygen) didn’t recognize the importance of their findings and misinterpreted. Their predecessor are not accountable for the discovery but they were capable of crafting the correct interpretation (what oxygen really was).

        • That is certainly one way of looking at the phenomenon. Another is that certain folks, like Trivers in this case, do the primary work and are the first to formalize a particular idea. Others then take the idea and ‘run with it,’ and especially discuss it in terms most normal folks can understand. Most early work in evolutionary theory of the sort Trivers was interested in was highly mathematical … folks like Gould and Dawkins distilled the math into words and ideas that most of us could understand. Some would say another example of the way you cast this phenomenon would be that of Darwin and Alfred Russell Wallace; perhaps Wallace came up with the idea first … but Darwin’s genius allowed him to see Natural Selection for what it really was.

          • And in the end the best that we can do is marvel at the leaps of genius that allow us to interpret that which is barely comprehensible at best. At the same time, though, it always seems to me that each time we reach one summit, what we find is one more daunting peak. And on it goes. As always. Thoroughly enjoyed the read, not only of the main article but also of the ensuing discussion. Haven’t had time for my own posts lately. Been busy with come contract work. Having fun though .. as always.

  4. Wow. What a dramatic photo of the seed pod! And a great explanation of life. (I only skipped a bit …). I enjoyed this very much! :-) I have to be certain that Lemony sees your seed pod. She found some the other day too.

    • I remember Lemony’s seed pods as well … very dramatic! Thank for checking in today George. I hope your weather down there is better than ours … we had 8″ overnight and I spent the entire morning digging out. Not fun. Have a great day. D

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