Home » Cell biology, Darwinism, News » Darwinism: Extensive “editing” of RNA requires no intelligent design?

Darwinism: Extensive “editing” of RNA requires no intelligent design?

octopus opens screwcap container/Matthias Kabel

In “Biochemistry: A Cold Editor Makes the Adaptation” (Science, February 17, 2012), Marie Öhman introduces an article that explains how life forms can live in very cold environments. Octopi and squid in particular, which adapt to tropics and poles, attracted research attention. It turns out that RNA gets edited to enable that, without changes in the genome sequence:

Although organisms have evolved to live in diverse conditions, closely related species often inhabit vastly different environments. This is particularly true for aquatic animals such as squid and octopus, which are common in tropical waters but are also found at the poles. These cephalopods have highly developed nervous systems, and one challenging question is how temperature-sensitive neuronal synaptic transmission has adapted to function at a near-freezing temperature. On page 848 of this issue, Garrett and Rosenthal (1) show that RNA editing rather than changes in the genome sequence enable potassium (K+) channels in octopus to function at different temperatures.

The abstract, “RNA Editing Underlies Temperature Adaptation in K+ Channels from Polar Octopuses” (Science 17 February 2012: Vol. 335 no. 6070 pp. 848-851
DOI: 10.1126/science.1212795) actually says they are “extensively edited” to enable a cold water switchover:

Abstract: To operate in the extreme cold, ion channels from psychrophiles must have evolved structural changes to compensate for their thermal environment. A reasonable assumption would be that the underlying adaptations lie within the encoding genes. Here, we show that delayed rectifier K+ channel genes from an Antarctic and a tropical octopus encode channels that differ at only four positions and display very similar behavior when expressed in Xenopus oocytes. However, the transcribed messenger RNAs are extensively edited, creating functional diversity. One editing site, which recodes an isoleucine to a valine in the channel*s pore, greatly accelerates gating kinetics by destabilizing the open state. This site is extensively edited in both Antarctic and Arctic species, but mostly unedited in tropical species. Thus adenosine-to-inosine RNA editing can respond to the physical environment.

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5 Responses to Darwinism: Extensive “editing” of RNA requires no intelligent design?

  1. Wow neo-Darwinism can even look ahead and develop sophisticated regulatory circuits to make precise adjustments for varying environments. :) Then again perhaps neo-Darwinism can’t do squat!

    Bacteria ‘Invest’ Wisely to Survive Uncertain Times, Scientists Report – November 2009
    Excerpt: “We have found that a particular genetic circuit is responsible for generating diversity within the bacteria population,”,,, “When conditions are highly variable, some individual bacteria are equipped to thrive in the highs or lows, while others tank,” ,, “There seems to be an optimization going on in these organisms,”,,, Essentially, variability of bacterial cells appears to match the variability in the environment,,,
    http://www.sciencedaily.com/re.....112102.htm

    Revisiting the Central Dogma in the 21st Century – James A. Shapiro – 2009
    Excerpt (Page 12): Genetic change is almost always the result of cellular action on the genome. These natural processes are analogous to human genetic engineering,,, (Page 14) Genome change arises as a consequence of natural genetic engineering, not from accidents.
    http://shapiro.bsd.uchicago.ed.....0Dogma.pdf

    A comparative approach for the investigation of biological information processing: An examination of the structure and function of computer hard drives and DNA – David J D’Onofrio1, Gary An – Jan. 2010
    Excerpt: It is also important to note that attempting to reprogram a cell’s operations by manipulating its components (mutations) is akin to attempting to reprogram a computer by manipulating the bits on the hard drive without fully understanding the context of the operating system. (T)he idea of redirecting cellular behavior by manipulating molecular switches may be fundamentally flawed; that concept is predicated on a simplistic view of cellular computing and control. Rather, (it) may be more fruitful to attempt to manipulate cells by changing their external inputs: in general, the majority of daily functions of a computer are achieved not through reprogramming, but rather the varied inputs the computer receives through its user interface and connections to other machines.
    http://www.tbiomed.com/content/7/1/3

    Biological Variation – Cornelius Hunter
    Excerpt: One hint that biology would not cooperate with Darwin’s theory came from the many examples of rapidly adapting populations. What evolutionists thought would require thousands or millions of years has been observed in laboratories and in the field, in an evolutionary blink of an eye.
    http://www.darwinspredictions......_variation

    Evolution of adaptive phenotypic traits without positive Darwinian selection – A L Hughes – November 2011
    Recent evidence suggests the frequent occurrence of a simple non-Darwinian (but non-Lamarckian) model for the evolution of adaptive phenotypic traits, here entitled the plasticity–relaxation–mutation (PRM) mechanism. This mechanism involves ancestral phenotypic plasticity followed by specialization in one alternative environment and thus the permanent expression of one alternative phenotype. Once this specialization occurs, purifying selection on the molecular basis of other phenotypes is relaxed. Finally, mutations that permanently eliminate the pathways leading to alternative phenotypes can be fixed by genetic drift. Although the generality of the PRM mechanism is at present unknown, I discuss evidence for its widespread occurrence, including the prevalence of exaptations in evolution, evidence that phenotypic plasticity has preceded adaptation in a number of taxa and evidence that adaptive traits have resulted from loss of alternative developmental pathways. The PRM mechanism can easily explain cases of explosive adaptive radiation,
    http://www.nature.com/hdy/jour.....1197a.html

    Plus, there is the little matter of the modern synthesis of neo-Darwinism being ‘dead’ which doesn’t bode well for their underlying presupposition in the study:

    The Fate of Darwinism: Evolution After the Modern Synthesis – January 2012
    Excerpt: We trace the history of the Modern Evolutionary Synthesis, and of genetic Darwinism generally, with a view to showing why, even in its current versions, it can no longer serve as a general framework for evolutionary theory. The main reason is empirical. Genetical Darwinism cannot accommodate the role of development (and of genes in development) in many evolutionary processes.
    http://www.springerlink.com/co.....03g3t7002/

    Peer-Reviewed Paper Concludes that Darwinism “Has Pretty Much Reached the End of Its Rope” – Jonathan M. – February , 2012
    Excerpt: Contrary to the Darwin lobby’s oft-repeated assertion that there are absolutely no weaknesses in Darwinian theory, the paper offers the concession that the modern synthesis has never provided an account of “how major forms of life evolved” — an omission that is not unsubstantial, to put it mildly.
    http://www.evolutionnews.org/2.....55941.html

    The Origin at 150: is a new evolutionary synthesis in sight? – Koonin – Nov. 2009
    Excerpt: The edifice of the modern synthesis has crumbled, apparently, beyond repair.
    http://www.arn.org/blogs/index....._synthesis

    Modern Synthesis of Neo-Darwinism (Genetic Reductionism) Is Dead – Paul Nelson – video
    http://www.metacafe.com/watch/5548184/

    A Piece from the Developmental Symphony – ENV – February 6, 2012
    Excerpt: Embryonic development is an astounding process that seems to happen “automatically.” The program is in place for the embryo to develop into an organism. While evolutionary biology can account for the many small changes that occur to fully grown organisms as a response to environmental pressures, it cannot account for the origin of a process that has every indication of having the end result in mind. The timing of each step is too precise and the complexity is too intricate to assume that these processes are the mere accumulation by happenstance of changes to regulatory genes. Each gene plays its role at a certain time, and like a symphony, each is activated and silenced in turn such that the final result is a grand performance of orchestrated effort that could only have occurred through design.

  2. However, the transcribed messenger RNAs are extensively edited, creating functional diversity. One editing site, which recodes an isoleucine to a valine in the channel*s pore, greatly accelerates gating kinetics by destabilizing the open state.

    This would appear to mean that “positive selection” takes place at the RNA level. This adds to the neo-Darwinian dilemma. ND already can’t explain all the seeming “positive selection” present in the genome in the form of polymorhpisms. Plus, does anyone dare to say that this invention occurred via neutral drift?

    Another day; another bad day for Darwinism.

  3. The editing and error correction mechanisms of the cell, together with related mechanisms like concatenation of partial protein sequences, are an absolutely astounding example of complex specified information. The idea that this stuff came about by chance is an absurdity of the highest order.

  4. Editing and error-correction require knowledge- knowledge of what to edit and how to edit, as well as when to edit.

  5. Editing and error-correction require knowledge- knowledge of what to edit and how to edit, as well as when to edit.

    Precisely. I am almost more astounded by the fact that any editing and error correction exists than the fact that the original system functions in the first place. Editing and error correction typically requires an even higher level of knowledge and understanding to implement.

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