Cell and body shape, and organism development does NOT depend exclusively on genetic information.
Kudo’s to Stephen C. Meyer’s book Darwin’s doubt, which provides in my view probably the biggest blow and clearest evidence against Darwins Theory of evolution, after Behe’s Darwin’s black box. Two books, which i highly recommend to anyone interested in ID theory, and origins of biodiversity.
NEO-DARWINISM AND THE CHALLENGE OF EPIGENETIC INFORMATION
These different sources of epigenetic information in embryonic cells pose an enormous challenge to the sufficiency of the neo-Darwinian mechanism. According to neo-Darwinism, new information, form, and structure arise from natural selection acting on random mutations arising at a very low level within the biological hierarchy—within the genetic text. Yet both body-plan formation during embryological development and major morphological innovation during the history of life depend upon a specificity of arrangement at a much higher level of the organizational hierarchy, a level that DNA alone does not determine. If DNA isn’t wholly responsible for the way an embryo develops— for body-plan morphogenesis—then DNA sequences can mutate indefinitely and still not produce a new body plan, regardless of the amount of time and the number of mutational trials available to the evolutionary process. Genetic mutations are simply the wrong tool for the job at hand. Even in a best-case scenario—one that ignores the immense improbability of generating new genes by mutation and selection—mutations in DNA sequence would merely produce new genetic information. But building a new body plan requires more than just genetic information. It requires both genetic and epigenetic information—information by definition that is not stored in DNA and thus cannot be generated by mutations to the DNA. It follows that the mechanism of natural selection acting on random mutations in DNA cannot by itself generate novel body plans, such as those that first arose in the Cambrian explosion.
Centrosomes play a central role in development: a frog egg can be induced to develop into a frog merely by injecting a sperm centrosome—no sperm DNA is needed. Another non-genetic factor involved in development is the membrane pattern of the egg cell.
FORM AND INFORMATION
Organismal form and function depend upon the precise arrangement of various constituents as they arise during, or contribute to, embryological development. Thus, the specific arrangement of the other building blocks of biological form—cells, clusters of similar cell types, dGRNs, tissues, and organs—also represent a kind of specified or functional information.
ABOVE AND BEYOND: EPIGENETIC INFORMATION
genes alone do not determine the three-dimensional form and structure of an animal. Developmental biologists, in particular, are now discovering more and more ways that crucial information for building body plans is imparted by the form and structure of embryonic cells, including information from both the unfertilized and fertilized egg. DNA helps direct protein synthesis. Parts of the DNA molecule also help to regulate the timing and expression of genetic information and the synthesis of various proteins within cells. Yet once proteins are synthesized, they must be arranged into higher-level systems of proteins and structures.
The three-dimensional structure or spatial architecture of embryonic cells plays important roles in determining body-plan formation during embryogenesis. Developmental biologists have identified several sources of epigenetic information in these cells.
The precise arrangement of microtubules in the cytoskeleton constitutes a form of critical structural information. neither the tubulin subunits, nor the genes that produce them, account for the differences in the shape of the microtubule arrays that distinguish different kinds of embryos and developmental pathways. Instead, the structure of the microtubule array itself is, once again, determined by the location and arrangement of its subunits, not the properties of the subunits themselves. Jonathan Wells explains it this way: “What matters in [embryological] development is the shape and location of microtubule arrays, and the shape and location of a microtubule array is not determined by its units.” Directed transport involves the cytoskeleton, but it also depends on spatially localized targets in the membrane that are in place before transport occurs. Developmental biologists have shown that these membrane patterns play a crucial role in the embryological development of fruit flies.
Preexisting membrane targets, already positioned on the inside surface of the egg cell, determine where these molecules will attach and how they will function. These membrane targets provide crucial information—spatial coordinates—for embryological development.
Ion Channels and Electromagnetic Fields
Experiments have shown that electromagnetic fields have “morphogenetic” effects—in other words, effects that influence the form of a developing organism. In particular, some experiments have shown that the targeted disturbance of these electric fields disrupts normal development in ways that suggest the fields are controlling morphogenesis.2 Artificially applied electric fields can induce and guide cell migration. There is also evidence that direct current can affect gene expression, meaning internally generated electric fields can provide spatial coordinates that guide embryogenesis.3 Although the ion channels that generate the fields consist of proteins that may be encoded by DNA (just as microtubules consist of subunits encoded by DNA), their pattern in the membrane is not. Thus, in addition to the information in DNA that encodes morphogenetic proteins, the spatial arrangement and distribution of these ion channels influences the development of the animal.
The Sugar Code
These sequence-specific information-rich structures influence the arrangement of different cell types during embryological development. Thus, some cell biologists now refer to the arrangements of sugar molecules as the “sugar code” and compare these sequences to the digitally encoded information stored in DNA. As biochemist Hans-Joachim Gabius notes, sugars provide a system with “high-density coding” that is “essential to allow cells to communicate efficiently and swiftly through complex surface interactions.” According to Gabius, “These [sugar] molecules surpass amino acids and nucleotides by far in information-storing capacity.” So the precisely arranged sugar molecules on the surface of cells clearly represent another source of information independent of that stored in DNA base sequences. These cascades are, along with the cell event itself, associated with the “coding information” on a cell surface, or, using another terminology, are realized due to an instruction for the cell from the morphogenetic field of an organism. The concrete signal transduction pathways connecting the “coding information” on a cell surface and the expression of the given sets of genes need to be elucidated.