A gene’s way

A few weeks ago, Steve Gingold posted lovely images of Painted Trillium.  He did so again, just the other day. Click the links to see specimens from west-central Massachusetts, then look below at Trillium I saw yesterday here in east-central Vermont. The former seem vigorous. The latter seems tired. Its mottled translucence and peaked blush tell me not that the individual is in poor health. To the contrary, I interpret these as sure signs of a plant making the transition between one physiological state and another. Signs of an individual whose genome has triggered a shift-in-gears, a change-in-strategy.

The stages of the life of a plant proceed, roughly, from seed, to embryo, seedling, mature plant, egg (ovule) and sperm (pollen), fertilization, fruit and to seed once again. There may be thousands of genes coding for the materials needed to accomplish each of these stages. And recognize that all of these aren’t needed all the time. So, genes must be regulated such that their products are only manufactured when called for.

A single Trillium plant may produce as many as fifty ovules. Once these are fertilized the plant must shift gears and move on to the business of setting seed and to preparing for the coming winter. There is no longer any need to attract pollinators and so the fancy petals and flashy pigments can go. It’s better, in an economic sense, to withdraw whatever materials might be available in those parts and to then shut them down.

The histories of all organisms have been such that they have, within limits imposed by the genome itself, maximized the efficiency with which they are able to make copies of themselves. They replicate because genes direct them to do so. To put a fine point on this argument, it is the genes that have evolved over millions of generations to maximize the efficiency with which they are able to direct the bodies of the organisms, within which they may be found, to make copies of themselves. Some would say that a Trillium plant is a Trillium gene’s way of making another Trillium gene. Think about that.


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