A short stretch of DNA is challenging what it means to be a species.
August 5, 2014
Excerpt: “Scientists have dubbed such regions of the genome “islands of speciation.” The persistence of such islands is a phenomenon that has been observed in a variety of organisms. Natural selection appears to put evolutionary pressure on these regions, which keeps both the genes and their corresponding traits distinct even in the face of interbreeding, while the rest of the genome can mix.”
My comment: Estrogen receptor α polymorphism in a species with alternative behavioral phenotypes details what appears to lie at the origin of species diversity in species from microbes to man in the context of these “islands of speciation.”
In their supporting information, the authors state: “The ZAL2 and ZAL2m alleles code for 597 amino acids, with two fixed differences driving a Val73Ile and Ala552Thr polymorphism in ZAL2m.” This links differences in parental feeding to nutrient-dependent pheromone-controlled amino acid substitutions that differentiate the cell types of all cells in all individuals of all species via conserved molecular mechanisms. Amino acid substitutions allow “islands of speciation” to emerge in the context of stabilized protein folding that is required for DNA to organize the genomes of what have consistently been referred to as different species.
For example, in the mouse-to-human model of cell type differentiation a valine to alanine substitution (similar to the one in the sparrows) differentiates the cell types of hair, teeth, sweat glands, and mammary tissue. See: Modeling Recent Human Evolution in Mice by Expression of a Selected EDAR Variant
However, when placed in to the context of chromosomal rearrangements in vertebrates, cause and effect is divorced from theories about mutation-initiated natural selection and the evolution of biodiversity. We can clearly see the differences between male mice and men, but we cannot see the similarities. Some evolutionary theorists hate to see such refutations of what they have offered as correlations based on observations and population genetics that this article politely states bastardized Darwin’s theory of evolution (with my emphasis below).
“Darwin, when he proved that species evolved, also proved there was no such thing as species,” said James Mallet….”
Population geneticists needed to show that species somehow evolved so they invented a theory of mutation-initiated natural selection and defined their terms before anyone realized that ecological variation leads to nutrient-dependent pheromone-controlled ecological adaptations via amino acid substitutions that link the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man.
The works on the white-throated sparrows have since exemplified cause and effect via the epigenetic effects of olfactory/pheromonal input on hormones that affect behavior in all vertebrates, such as crows, but also the invertebrates — like the butterflies mentioned here. Now, the theorists are scrambling to redefine their terms and refer to epigenetically-effected cell type differentiation in the context of epimutations, which are not fixed in the organized genomes, because no experimental evidence has shown that mutations are ever fixed in organized genomes.
If they ever were, there could be no such thing as the evolution of biodiversity because nutrient-dependent pheromone-controlled amino acid substitutions enable rapid changes to occur in organized genomes via chromosomal rearrangements. Mutations perturb the protein folding that’s required for the plasticity of changes that must accompany ecological changes manifested in chromosomal rearrangements, which makes mutation-driven evolution a ridiculously implausible theory. Fortunately, Israeli middle-schools now teach the theory of evolution in the context of what is known about ecological variation and how it leads to ecological adaptations manifested in the morphological and behavioral phenotype of species from microbes to man.
Indeed, there may be many researchers who were trained in Israel and do not believe in theories when it comes to what’s required for them to establish biologically-based cause and effect, which is experimental evidence of it, preferably in model organisms. See for example: Starvation-Induced Transgenerational Inheritance of Small RNAs in C. elegans. Clearly, what Darwin proved is that there is no such thing as a species in the context of fixation. At the same time, he showed that ‘conditions of life’ led to ecological adaptations, or to extinction.
Apparently, he knew from intuition and observations that organisms that do not eat do not mutate into other organisms; they starve to death. Surprisingly, evolutionary theorists may not have observed that, or do not think it is important enough to consider in the context of their stories.