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A project by Stephen L. Talbott

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Genes and the Central Fallacy of Evolutionary Theory

Summary

Evolution is said to occur inevitably, given (1) trait variation among members of a breeding population, (2) at least some inheritance of parental traits by offspring, and (3) differential fitness of organisms possessing different traits. This core logic of evolutionary theory has been strongly grounded in DNA: the heritable substance consists essentially of DNA; variation equates to random DNA mutations; and differential fitness derives from the phenotype (observable features) of the organism, which in turn derive from instructions in DNA. This entire logic is so far abstracted from the life of organisms that, by itself, it tells us little if anything about the actual possibilities or likely character of evolutionary change.

Three lines of thought have supported the conviction that DNA is the essential hereditary substance. One is rooted in the belief that DNA is digital, consisting of stable and discrete (“atomic”) units that are reliably replicated from one generation to the next, subject only to occasional mutations. Advantageous mutations can then spread in the population through natural selection, while disadvantageous ones are eliminated. This measured change against a background of stability is supposed to be what makes possible the cumulative development of complex adaptive features in an evolutionary lineage.

Another key conviction is that DNA, in some fundamental sense that is never made clear, explains the organism. Whatever is critically important for explaining the organism is naturally assumed to be critically important for inheritance. And, in the third place, there is the longstanding disconnect between evolutionary studies and those, such as embryology, related to organismal development. This disconnect is symbolized by by the isolation of DNA from its cellular surroundings and, on a larger scale, by the isolation of the germline from somatic cells. And it is strengthened by the apparent failure of Lamarckianism (inheritance of acquired characteristics, such as the enlarged biceps of the blacksmith): if traits acquired by organisms during the course of their development cannot be inherited, it must be because they cannot find their way into the decisive heritable substance (DNA).

We can recognize in all the foregoing the Genetic Dogma of Evolutionary Theory: The tale of evolution is, in one sense or another, the tale of a single, overwhelmingly dominant, stable heritable substance slowly changing over time and explaining the organism. This heritable substance is DNA.

The misdirection in this dogma lies in the fact that it posits DNA as a clearly definable and static thing, a single substance that can be analyzed out of an almost infinitely complex, functioning whole and treated in this disconnected state as if it held the decisive causal explanation for the canonical form and character of that whole. In reality the organism is a living agent whose life as a whole is a pursuit of its own ends and meanings. Its significant bequest to future generations consists of an elaborately chosen projection of its own life — not some single “controlling” molecular element — into a nascent life that is never less than a complete organism. This organism, as a physical entity, is without a beginning in any absolute sense. Its life is a continuation and transformation of the developmental and purposive existence of its progenitors.

The developmental powers of the individual organism are illustrated in the dramatic processes of metamorphosis whereby, for example, a crawling larva is transformed into a flying butterfly with the same DNA, and in the equally dramatic processes by which the single-celled human zygote differentiates into hundreds or thousands of cell types with the same DNA. Here we see the power of the organism as a whole to transform — radically, coherently, and stably — its cells and its overall form without this transformation being attributable to DNA as First Cause.

After all, it makes no sense to say that the numerous divergent pathways from the zygote to the various cell types of the body are explained by the one thing in the cells that remains more or less the same, namely, the bare DNA sequence, unstructured by the organism’s developmental processes. There is no foundational explanatory power offered by some fixed structure to which molecular nuts and bolts, gears and levers — or informational “particles” — can be neatly added, subtracted, or substituted for each other in isolation from larger processes. Yet every lineage of cells proceeds along its path in a perfectly coherent, well-organized way, with transformations occurring in a proper, adaptable, and fluent order.

The zygote’s transformation along the pathway from single, fertilized cell to mature organism is an activity, a story, of the entire cell and entire organism. Life scientists, from molecular biologists to naturalists, routinely do describe the organism’s life in narrative terms (see “The Unbearable Wholeness of Beings”), and it is the character of the narrative that must change in a coherent manner from generation to generation if evolution is to occur. It must change in the only way an integral narrative context can change, through a continual mutual adjustment of directed activities.

The one-celled zygote is the heritable substance. And it is absurd to imagine it developing into an organism under the autocratic control of just one of the contents it effectively coordinates; it already is the whole organism.

The belief that evolution depends overwhelmingly on the literal replication of a single type of molecule has been assumed more than it has been defended. It certainly has not been adequately defended against the idea that evolution is rooted in whole-organism inheritance — inheritance such as we find embodied in the coordinated and stable intentions of a living zygote.

What really needs perpetuation in an evolutionary lineage is a distinctive, cognitively informed dynamic of growth and development. And this is exactly what nature shows us. Every feature of the organism, considered as a thing (the blacksmith’s arm, with enlarged biceps), is a product of the organism’s life, not the life itself. It is a product of the ever-striving, adaptive capacities that define this kind of organism. In relation to a living notion of inheritance, the traditional arguments against the inheritance of acquired characteristics are irrelevant. We don’t need a woodenly literal passing on of isolated features in order for offspring to receive a meaningful bequest from their parents. The true bequest reflects (as does every cell of the parents’ bodies) something of the parents’ life experience in their particular environment.

Before we claim that the organism’s wisdom in pursuing its own development has nothing to do with evolution, we might want to ask ourselves whether there is reason why any creature should be less expert at managing its reproductive organs and gametes in relation to their distinctive purposes and environmental context than it is at managing its heart and lungs. A great deal of research today focuses on the various processes that make a lie of the supposed isolation of the germline cells from the organism as a whole.

With the demise of the gene as the single, decisive heritable substance, the core logic of received evolutionary theory is shown to be an empty shell, disconnected from living activity.

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Selected excerpts from the chapter
bullet The organism as agent of its own development (1)
bullet The organism as agent of its own development (2)
bullet The organism as agent of its own development (3)
bullet The organism as agent of its own development (4)
bullet Development is a transformation of the whole (1)
bullet Development is a transformation of the whole (2)
bullet The organism is an activity, not a thing (1)
bullet The organism is an activity, not a thing (2)
bullet Contexts and activities, not things, are inherited (1)
bullet Contexts and activities, not things, are inherited (2)
bullet Acquired characteristics versus active potentials
bullet The organism manages its own germline (1)
bullet The organism manages its own germline (2)
bullet The organism manages its own germline (3)
bullet The organism manages its own germline (4)
bullet A logic hollow at its core
bullet Yes, holism is difficult