The importance of cell membranes

_{Denyse O'Leary

May 29, 2014

Cell biology, News}

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Membrane Patterns Carry Ontogenetic Information That Is Specified Independently of DNA

Abstract: Embryo development (ontogeny) depends on developmental gene regulatory networks (dGRNs), but dGRNs depend on pre-existing spatial anisotropies that are defined by early embryonic axes, and those axes are established long before the embryo’s dGRNs are put in place. For example, the anterior-posterior axis in Drosophila and the animal-vegetal axis in Xenopus and echinoderms are initially derived from the architecture of the ovary through processes mediated by cytoskeletal and membrane patterns rather than dGRNs. This review focuses on plasma membrane patterns, which serve essential ontogenetic functions by providing targets and sources for intracellular signaling and transport, by regulating cell-cell interactions, and by generating endogenous electric fields that provide three-dimensional coordinate systems for embryo development. Membrane patterns are not specified by DNA sequences. Because of processes such as RNA splicing, RNA editing, protein splicing, alternative protein folding, and glycosylation, DNA sequences do not specify the final functional forms of most membrane components. Still less does DNA specify the spatial arrangements of those components. Yet their spatial arrangements carry essential ontogenetic information. The fact that membrane patterns carry ontogenetic information that is not specified by DNA poses a problem for any theory of evolution (such as Neo-Darwinism) that attributes the origin of evolutionary novelties to changes in a genetic program—-whether at the level of DNA sequences or dGRNs. This review concludes by suggesting that relational biology and category theory might be a promising new approach to understanding how the ontogenetic information in membrane patterns could be specified and undergo the orchestrated changes needed for embryo development.

See also: Metabolome: Big differences between humans and apes and monkeys

Comments

And, as Dr. Paul Nelson and Dr. Stephen Meyer have shown previously, even tampering with that part of the developmental gene regulatory networks (dGRNs) located within the DNA is ‘always catastrophically bad’
I presume that precludes any tampering by a designer as well?Mung_{May 29, 2014
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And, as Dr. Paul Nelson and Dr. Stephen Meyer have shown previously, even tampering with that part of the developmental gene regulatory networks (dGRNs) located within the DNA is 'always catastrophically bad'
A Listener's Guide to the Meyer-Marshall Debate: Focus on the Origin of Information Question -Casey Luskin - December 4, 2013 Excerpt: "There is always an observable consequence if a dGRN (developmental gene regulatory network) subcircuit is interrupted. Since these consequences are always catastrophically bad, flexibility is minimal, and since the subcircuits are all interconnected, the whole network partakes of the quality that there is only one way for things to work. And indeed the embryos of each species develop in only one way." - Eric Davidson http://www.evolutionnews.org/2013/12/a_listeners_gui079811.html Darwin or Design? - Paul Nelson at Saddleback Church - Nov. 2012 - ontogenetic depth (excellent update) - video Text from one of the Saddleback slides: 1. Animal body plans are built in each generation by a stepwise process, from the fertilized egg to the many cells of the adult. The earliest stages in this process determine what follows. 2. Thus, to change -- that is, to evolve -- any body plan, mutations expressed early in development must occur, be viable, and be stably transmitted to offspring. 3. But such early-acting mutations of global effect are those least likely to be tolerated by the embryo. Losses of structures are the only exception to this otherwise universal generalization about animal development and evolution. Many species will tolerate phenotypic losses if their local (environmental) circumstances are favorable. Hence island or cave fauna often lose (for instance) wings or eyes. http://www.saddleback.com/mc/m/7ece8/
Of related note to 'spatial arrangements' not being reducible to DNA, chimps and humans differ by orders of magnitude in their 'genomic architecture':
"Where (chimps and humans) really differ, and they differ by orders of magnitude, is in the genomic architecture outside the protein coding regions. They are vastly, vastly, different.,, The structural, the organization, the regulatory sequences, the hierarchy for how things are organized and used are vastly different between a chimpanzee and a human being in their genomes." Raymond Bohlin (quoted per Richard Sternberg) - 9:29 minute mark of video http://www.metacafe.com/watch/8593991/
also of note, Gene regulation is very different between humans and chimps:
Gene Regulation Differences Between Humans, Chimpanzees Very Complex – Oct. 17, 2013 Excerpt: Although humans and chimpanzees share,, similar genomes (70% per Tomkins), previous studies have shown that the species evolved major differences in mRNA expression levels.,,, http://www.sciencedaily.com/releases/2013/10/131017144632.htm Evolution by Splicing – Comparing gene transcripts from different species reveals surprising splicing diversity. – Ruth Williams – December 20, 2012 Excerpt: A major question in vertebrate evolutionary biology is “how do physical and behavioral differences arise if we have a very similar set of genes to that of the mouse, chicken, or frog?”,,, A commonly discussed mechanism was variable levels of gene expression, but both Blencowe and Chris Burge,,, found that gene expression is relatively conserved among species. On the other hand, the papers show that most alternative splicing events differ widely between even closely related species. “The alternative splicing patterns are very different even between humans and chimpanzees,” said Blencowe.,,, http://www.the-scientist.com/?articles.view%2FarticleNo%2F33782%2Ftitle%2FEvolution-by-Splicing%2F
Thus where Darwinian theory needs the most plasticity in order to be viable as a hypothesis, i.e. in developmental gene regulatory networks, is where it is found to be least flexible. Yet, it is in these developmental gene regulatory networks where the greatest differences are found! ,,, If neo-Darwinism were a normal science, instead of being mainly a cornerstone of the atheistic religion, this finding, along with many other lines of evidence (J. Shapiro etc,,) would be enough to overturn it as a hypothesis of serious consideration in science.bornagain77_{May 29, 2014
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