
Tiny, Vast Windows Into Human DNA
By CARL ZIMMER
Excerpt 1): “Sometimes, a single transcription factor may switch on dozens of other genes. And sometimes, those genes encode transcription factors of their own, enabling a cell to produce hundreds of kinds of molecules at once.”
Excerpt 2): “Flies, worms and humans come from distant branches on the evolutionary tree. The last common ancestor lived 700 million years ago.”
My comment: In our 1996 Hormones and Behavior review article, we linked what was known about molecular epigenetics and cell type differentiation in species from microbes to man via the conserved molecular mechanisms of nutrient-dependent pheromone-controlled ecological adaptations.
“Molecular epigenetics
Yet another kind of epigenetic imprinting occurs in species as diverse as yeast, Drosophila, mice, and humans and is based upon small DNA-binding proteins called “chromo domain” proteins, e.g., polycomb. These proteins affect chromatin structure, often in telomeric regions, and thereby affect transcription and silencing of various genes (Saunders, Chue, Goebl, Craig, Clark, Powers, Eissenberg, Elgin, Rothfield, and Earnshaw, 1993; Singh, Miller, Pearce, Kothary, Burton, Paro, James, and Gaunt, 1991; Trofatter, Long, Murrell, Stotler, Gusella, and Buckler, 1995). Small intranuclear proteins also participate in generating alternative splicing techniques of pre-mRNA and, by this mechanism, contribute to sexual differentiation in at least two species, Drosophila melanogaster and Caenorhabditis elegans (Adler and Hajduk, 1994; de Bono, Zarkower, and Hodgkin, 1995; Ge, Zuo, and Manley, 1991; Green, 1991; Parkhurst and Meneely, 1994; Wilkins, 1995; Wolfner, 1988). That similar proteins perform functions in humans suggests the possibility that some human sex differences may arise from alternative splicings of otherwise identical genes.
Serious scientists understand the fact that sex differences in cell types of yeasts reflect all nutrient-dependent differences in cell types of tissues in organs of organ systems in flies (Drosophila melanogaster), worms (Caenorhabditis elegans), and humans. Science journalists like Carl Zimmer insist on portraying cell type differentiation as if it occurred during the past 700 million years.
Zimmer: “The last common ancestor lived 700 million years ago.”
Jordan et al., (2005): “We cannot conceive of a global external factor that could cause, during this time, parallel evolution of amino acid compositions of proteins in 15 diverse taxa that represent all three domains of life and span a wide range of lifestyles and environments. Thus, currently, the most plausible hypothesis is that we are observing a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms.”
The fact that nutrient-dependent amino acid substitutions differentiate all cell types in all species has not deterred Zimmer and others from portraying cell type differentiation as if it occurred in the context of mutations, natural selection, and the evolution of biodiversity over hundreds of millions of years.
The fact that no evolutionary events suggest evolution ever occurred, seems pointless to mention to people like Zimmer.
We will no doubt continue to see him portray new evidence of biologically-based cause and effect in flies and worms in the ridiculous context of evolved morphological and behavioral phenotypes, until someone invites him to try to explain why he still believes in the neo-Darwinian theory of evolution when it has never been supported by any experimental evidence whatsoever. For contrast, see:
Genomes in turmoil: Quantification of genome dynamics in prokaryote supergenomes
“…evolutionary events (hereinafter Genome Dynamics Events or GDE)…”
Starvation-Induced Transgenerational Inheritance of Small RNAs in C. elegans
“…starvation-induced small RNAs are transmitted transgenerationally, providing a mean for starved worms to control the expression of relevant genes in consecutive generations.”
Clearly, if any species could not control its nutrient-dependent pheromone-controlled reproduction, the species would not be the last universal common ancestor of all organisms that manifest their nutrient-dependent pheromone-controlled morphological and behavioral phenotypes in the extant biodiversity of species from microbes to man.
See also: Baby talk: More misrepresentations of ecological adaptations