Science journal posits non-Darwinian mechanisms of evolution

The below article, appearing at a pro-ID website, and summarizing and linking an article in Nature Physics by Mark Buchanan, supplements the recent VFR post on the view of the late molecular biologist Richard Strohman that evolution may work by feedback from the environment to the organism, and from the organism as a whole to the organism’s DNA. The summary is not terribly clear, as the author, David Tyler, does not explain Buchanan’s main concept of “horizontal gene tranfer.” But the news is that an article challenging Darwinian genetic reductionism and exploring mechanisms compatible with Lamarkianism has been published in an establishment science publication.

The collectivist challenge to Darwinism
by David Tyler 09:13:44 am, Categories: Literature—Articles, 890 words English (UK)

The general public is led to think that Charles Darwin magnificently solved the problems associated with the emergence of biological complexity. Many opinion-formers write confidently about the revolution triggered by the publication of “On the origin of species” in 1859. These people have developed a ‘consensus’ position which they use to convince scientific societies, policy makers, funding agencies and educationalists that any dilution of Darwinism is a retrograde step, ushering in a dark age for science. What will they make—and what will we make—of an essay in Nature Physics that talks about breaking with “many of the presuppositions of traditional evolutionary thinking” and highlights its message with these words:

“A coming revolution may go so far as to unseat Darwinian evolution as the key explanatory process in biology.”

The essay is a contribution to cross-disciplinary thinking. It starts with an awareness of collective phenomena in modern physics. Thinking has moved away from reductionism and is adopting a holistic interactionism. The new focus is:

”- on the fundamentals of phase transitions and other ordering phenomena in condensed-matter systems, on pattern formation out of equilibrium, and on the rich cooperative dynamics of granular and glassy systems, polymers and other forms of ‘soft matter’, or charge carriers in high-temperature superconductors and other exotic materials.”

The writer, Mark Buchanan, sees a parallel between physics and biology. The tools of physics and engineering are already being used to understand interacting networks within biological systems:

“It now seems clear that biology may also have a second act linked to the widespread importance of collective phenomena. The explosion of genetic and proteomic data, of course, has ushered in the era of systems biology, as biologists have come to recognize the need to gain a more holistic understanding of the functioning of organisms.”

However, it is horizontal gene transfer that is perceived to be ushering in the overthrow of Darwinism. This is because all the mechanisms that are being seriously discussed to account for the data invoke environmental influences/drivers. Buchanan argues that the phenomenon can be regarded as confirmed, even though our understanding of mechanisms is in its infancy.

“The clear impact of horizontal gene transfer on bacterial evolution has been established only fairly recently using large-scale genome sequencing, and in the context of a small number of bacteria. Biologists have only begun exploring the various environmental factors that promote or limit horizontal gene transfer, and know almost nothing of how this mechanism of genetic sharing influences the overall logic of the evolutionary process itself.”

Why does this take us beyond Darwinism? It is because the mechanisms of Darwinian evolution are inherently reductionistic, with individual life forms struggling for survival in competition with other individuals. Within Darwinian theory, the environment acts as a filter, allowing the fit to live on. Horizontal gene transfer (HGT) moves us away from individuals and towards breeding populations, and the environment becomes a driver of genetic change rather than a passive filter. The tree of life now looks like an unstructured bush (for more, see here).

“[T]he apparent ubiquity of horizontal gene transfer implies that microorganisms have an impressive capacity to actively alter their genomes in response to environmental stresses or opportunities, and this capability is intimately linked to their involvement in a larger community in which the diversity of genetic material resides. Consequently, […] the basic concept of an organism as an isolated biological entity with a unique genetic make-up makes little sense in the bacterial world, as the genetic repertoire of an entire population, as well as foreign species, is available to any individual within it.”

Talk of unseating Darwinian evolution has not gone down well with some. Larry Moran quotes some of Buchanan’s visionary words and declares: “This kind of hyperbole is not helpful. Shame on Nature Physics for publishing it.” However, we could do with more substance in arguments against this essay. Darwinism is inherently reductionistic and it can devise ways of framing HGT to fit into its own mental models. But what it cannot easily do is adopt the holistic perspectives that are emerging everywhere. This is why some of us find a framework of design to be compelling. Design provides a coherent context for systems biology, for biomimetics, and for many other contemporary areas of research. Furthermore, although our understanding of HGT is imperfect and in its infancy, design thinking provides a warrant for inferring the origin of genes capable of being transferred, and for understanding the roles played by HGT in populations.

Collectivist revolution in evolution
Mark Buchanan
Nature Physics, 5(8), (August 2009), 531-531 | doi:10.1038/nphys1352 (Text here)

Last few sentences: The conjecture is that horizontal gene transfer was indeed required for the present genetic code to take the form it has, and that the emergence of life most likely went through a series of stages, with the early stage more Lamarckian in character, and only the latter stages becoming more Darwinian.

Exploring that point in greater detail will be a task for a new kind of biology, one that breaks with many of the presuppositions of traditional evolutionary thinking, and explores the potential for rich and surprising dynamics in a collective setting. It will almost surely benefit from the ideas and experience of physics, which has already experienced its own collectivist revolution.

Posted by Lawrence Auster at August 23, 2009 04:01 PM | Send

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