Monday, March 25, 2013

Reversible Evolution, or, Tessellating Rhetoric

(image taken from Threading on Thin Ice)

(image taken from Strange Paths)

Earlier last week, I stumbled upon a titillating headline for a popular media article on some interesting new research in evolutionary and behavioral biology: the article proclaims evidence had been compiled illustrating "reversible evolution" in a phylogenetic mapping study of dust mites, in which certain species of the lowly, despised creatures that plague homes across the globe had evolved from free-living organisms to parasitic living structures to free-living once again. Additionally, the headline announces that these findings contradict  a "deeply rooted biological principle," known as Dollo's law, a hypothesis generated over one hundred years ago by French-Belgian paleontologist Louis Dollo. In the article, Dollo's law is described as such: "evolution is not reversible."

Obviously, such charged and potentially misleading diction as reversible and irreversible evolution immediately baited my interest, as a perpetual student of biology, of behavior, of evolutionary psychology, of the history of science, and of issues of science literacy and its iterations in popular media. After reading the superficial explanation of the dust mite study and the purported implications on evolutionary theory, based on some flimsy assumptions from Dollo's law, my interest was ignited further. To invoke Dollo's law, without appropriate historical, philosophical, or scientific context, is lazy and potentially dangerous, no matter the intentions. While digging deeper into this concept, to find the context that the popular article lacked, I stumbled on this book chapter by Stephen Jay Gould.  Importantly, and articulately, the meditation outlines the history of biology, and the milieu in which Dollo was writing and espousing his ideas, and more specifically, outlines the paleontological approach and outlook that steered his entire perspective on evolutionary laws and their functions. Critical to note, as a paleontologist, Dollo is studying phylogenies and the evolution of specific morphological traits retrospectively, in the fossil record; by stating that the development of a particular morphological trait in a specific environment is irreversible, he is setting a precedent that convergences of adaptive traits between organisms and their ancestors are discernible, and therefore, as Gould highlights, "paleontology is a worthwhile endeavor." 

Gould also elegantly explains, with illustrating examples from Dollo's own writings, that Dollo never proposed a dogmatic, unyielding irreversibility for all evolutionary events; rather, his tenets should be understood as organisms never return exactly to a former state, and vestiges of its arc of morphological development remain, allowing for the creation of phylogenies. Again, his postulates are hinged on the defense of paleontology as a productive and fruitful exercise, and outright acknowledge the incomplete nature of the fossil record. Now, as then, even with advancing technology and broader understanding of critical biological, biochemical, and physical forces, the arcane, puzzle-piece qualities of floral and fauna fossils can inhibit and prohibit a complete, and confidently accurate, picture of what occurred historically. And therein is the beauty of continued research and continued fervor for truth and understanding; there is always more to learn. 

The study in question, with the dust mites, is also retrospectively analyzing their evolutionary trajectory, but, unlike Dollo and his contemporaries, the research team has the entire field of genetics, as well as collaborative networks of genetic data samples from various laboratories, as an ally and a resource, and, not inconsequentially, as fundamental understanding and context. What I found that the article also lacked, in terms of detail and nuance, was also outlined by Gould in his portrait of Dollo and his evolutionary ideas: the notion of complexity and that a precise, exact reversal of complex traits does not occur, as this would require, it is now understood, the individual organisms, and thereby a population, to meticulous retrace a long series of particular biochemical, genetic, behavioral, and environmental steps, which interact and do not enact exclusively of the others, in a systematic order. While, certainly and rightly, the evidence that a parasitic organism, whose ancestors had been free-living, has evolved to be free-living once more is exciting and fascinating, it must be understood that this occurred from a confluence and a network of genetic and environmental circumstances. As the Huffington Post article may suggest, this was not some single step, which happened suddenly and without cause. In a country where even the most basic premises of biology are misunderstood and misconstrued, notably the basic definition of the theory of evolution by natural selection, such a cavalier reference to Dollo's ideas disappoints me.

After I read the initial account of the dust mite study, once my anger and frustration over the disregard for specific and meaningful jargon and historical context subsided, I did some research to try to glean more information. Spending a few hours, in between teleconferences and various tasks at work, I found over a dozen articles, all essentially written with the exact same words, as though each were just slight variations of the same press release, printed over and over, shifted slightly in form, a journalistic tessellation. General scientific rhetoric repeated across various news sites and popular blogs, like some sycophantic soundbites. So, the guilt of incomplete or misleading reporting lies with many. 

Perhaps coincidentally, the universe working in synchronistic ways, a few days later, I idly followed some furious Twitter dialogues from a series of my favorite science bloggers and science writers, apparently in response to lectures at a evolution and communication conference, many about the peril of perpetuating, among lay audiences, the notion that evolution is directional, as though moving in particular paths, because this can easily be mis-translated or processed as progress, or regress. One prevailing concern, relevant to this dust mite story, was the visual depiction of phylogenetic trees, which, inherently, branch out or branch down, either way connoting a path or a track. For those familiar with reading such schematics, although the subconscious inclination may be to view them as directional, they are understood to, instead, be tools and, well, mere schematics, rather than veritable representations of precise mechanisms of evolution. Naturally, they are created as accurately as possible, given available conclusive evidence, but, it seems, those fluent in biology know how to infuse some flexibility and some perspective in their use.

As someone who has worked in journalism and media before, I understand the constraints under all reporters, predominantly time and space, and to a different extent, audience. For those writing about scientific research, these pressures are further exacerbated; they, themselves, have a limited time to synthesize and interpret this new information, digest it and be able to regurgitate it for the masses, and be able to do so within word count and with enough compelling pull to, hopefully, maybe, draw the eye of those who could care less about dust mites and how they are now living. There is a not insignificant preponderance of journalists and media types in my social circle; not one of them formally studied a physical science, and life has surely taught me this is not a coincidence. So, while the demons of time and space must be reckoned, there should still be a commitment to integrity, to an objective portrayal of new and exciting research. Like evolution, the barriers to scientific literacy, solvency, appreciation, wonder, engagement, are not linear; our problems here in objective presentation and critical engagement with new fields of research, and with new as well as historical scientific postulates, are cyclic. And we will continue to re-trace our steps, perhaps not precisely, without further education and further demand for context, detail, and more astute explanation.

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