Nova hipótese evolucionária: evolução baseada em interação - como que a seleção natural e a mutação não aleatória trabalham juntas

quinta-feira, outubro 24, 2013


Interaction-based evolution: how natural selection and nonrandom mutation work together

Adi Livnat

Correspondence: Adi Livnat

Author Affiliations

Biology Direct 2013, 8:24 doi:10.1186/1745-6150-8-24

Published: 18 October 2013

Abstract (provisional)


The modern evolutionary synthesis leaves unresolved some of the most fundamental, long-standing questions in evolutionary biology: What is the role of sex in evolution? How does complex adaptation evolve? How can selection operate effectively on genetic interactions? More recently, the molecular biology and genomics revolutions have raised a host of critical new questions, through empirical findings that the modern synthesis fails to explain: for example, the discovery of de novo genes; the immense constructive role of transposable elements in evolution; genetic variance and biochemical activity that go far beyond what traditional natural selection can maintain; perplexing cases of molecular parallelism; and more.

Presentation of the hypothesis

Here I address these questions from a unified perspective, by means of a new mechanistic view of evolution that offers a novel connection between selection on the phenotype and genetic evolutionary change (while relying, like the traditional theory, on natural selection as the only source of feedback on the fit between an organism and its environment). I hypothesize that the mutation that is of relevance for the evolution of complex adaptation?while not Lamarckian, or "directed" to increase fitness?is not random, but is instead the outcome of a complex and continually evolving biological process that combines information from multiple loci into one. This allows selection on a fleeting combination of interacting alleles at different loci to have a hereditary effect according to the combination's fitness.

Testing the hypothesis

Empirical evidence for the proposed mechanism from both molecular evolution and evolution at the organismal level is discussed, and multiple predictions are offered by which it may be tested.

Implications of the hypothesis

This proposed mechanism addresses the problem of how beneficial genetic interactions can evolve under selection, and also offers an intuitive explanation for the role of sex in evolution, which focuses on sex as the generator of genetic combinations. Importantly, it also implies that genetic variation that has appeared neutral through the lens of traditional theory can actually experience selection on interactions and thus has a much greater adaptive potential than previously considered.

Reviewers: This article was reviewed by Nigel Goldenfeld (nominated by Eugene V. Koonin), Jurgen Brosius and W. Ford Doolittle.


FREE PDF GRATIS: Biology Direct



" is commonly assumed that traditional natural selection operates to the extent that it can, and that originally neutral mutations account for anything that selection does not account for. But this modern approach leads to a deep inconsistency. The original idea of natural selection and random mutation, implicit in Fisher’s work, was to minimize the amount of 'work' done by chance in the evolution of adaptation and let natural selection do the job of evolving an adaptation by pulling out from the noise the supposed slightly beneficial mutations and causing them to accumulate inexorably toward the evolution of adaptation. It is inconsistent to invoke this idea, which attempted to minimize the amount of evolutionary work done by fortuitous chance, while at the same time allowing for an unspecified number of originally neutral mutations to play an inherent role in the evolution of adaptation, as is currently done for example in the case of de novo genes. Indeed, there is no quantification of the amount of chance that we call upon to explain the evolution of adaptation (namely the chance that is involved in the arising of accidental mutations and in random genetic drift, to the extent that the latter is invoked)—a deep problem not yet addressed at all by the whole body of population genetics."



Quando escrevo aqui que a teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionários (de A a Z, vai que...), a Galera dos meninos e meninas de Darwin reage dizendo que eu não entendo o componente teórico da teoria da evolução. A cada dia os evolucionistas me vindicam com suas pesquisas. Ah, como é bom ser vindicado por evolucionistas. Sinal de que estou em boa companhia, pelo menos no que diz respeito ao status heurístico de uma teoria que não se corrobora no contexto de justificação teórica desde 1859.

Fui, nem sei por que, rindo igual o gato de Cheshire...