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. — Jordan et al., (2005)
The increase in the number of amino acids, which is linked to the exponential increase in the number of functional proteins in species from microbes to man, needs to be discussed among physicists, chemists, and molecular biologists. Discussion must be among those who are less concerned about face-saving than they are about the dissemination of accurate information. See for example: Massive isotopic effect in vacuum UV photodissociation of N2 and implications for meteorite data
The N-isotopic fraction during VUV photodissociation is presented here and exhibits an unprecedented isotopic enrichment at specific wavelengths, arising due to the predissociative nature of dissociation via complex multiple (excited) state mixing. It is highly plausible that the entire meteoritic N-isotope range can be accommodated simply by the photochemical effect (including self-shielding and mutual shielding and perturbations) during photodissociation of N2. The bulk nebular N-isotopic ratio is represented by the Sun and Jupiter, while the terrestrial ratio and the ratios from the meteoritic materials represent considerable processing from the original starting values, and the bulk of the processing must have occurred in the solar nebula.
Reported as: No need for extrasolar delivery by comet: Nitrogen fingerprint in biomolecules could be from early Sun
Excerpt: “New experiments using a powerful source of ultraviolet light have shown that no extra-solar explanation is needed and the chemistry is straight forward…”
My comment: Try to tell a theoretical physicist that their ideas about the deep space (extrasolar) origins of life and/or 14 billion years it took for the evolution from microbes to humans are pseudoscientific nonsense in the context of what is known about ecological variation and cell type differentiation. They will lash out while continuing to ignore inconvenient data or invent more 2nd laws of thermodynamics. See: The second laws of quantum thermodynamics
Unless people like Bo O. Zhou are willing to enter discussions about physics and chemisty, theorists will no doubt continue to hide from molecular biologists who know that cell type differentiation is nutrient-dependent and RNA-mediated, not driven by mutations and evolution across billions or millions of years. For example, at the origin of this discussion ‘Chain reaction’ spreads gene through insects, Bo O. Zhou wrote: “This is not surprising at all. If you cross CMV-cre male to floxed females, all the offsprings are flox-deleted. It is the same mechanism.”
It’s the same mechanism because ecological variation leads to ecological adaptations via the biophysically constrained chemistry of nutrient-dependent RNA-mediated protein folding in all organisms on this planet. See the published work that Bo O. Zhou co-authored in 2011: Recent Transcription-induced Histone H3 Lysine 4 (H3K4) Methylation Inhibits Gene Reactivation.
Excerpt: Chromatin, the physiological template of all eukaryotic genetic information, is made of repeating nucleosomes. Each nucleosome consists of 147-bp DNA wrapping around a histone octamer, including two each of H2A, H2B, H3, and H4 (1). In the process of gene transcription, chromatin structure can be modulated at several levels, such as ATP-dependent chromatin remodeling (2), histone modifications (3), and nucleosome disassembly and reassembly (4).
My comment: ATP-dependent chromatin remodeling appears to be nutrient-dependent and pheromone-controlled via the conserved molecular mechanisms we detailed in the molecular epigentics section of our 1996 Hormones and Behavior review: From Fertilization to Adult Sexual Behavior, which is also available here.
Excerpt: “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…”
SARCASM ALERT But wait – look over there… I think I found a way to invent the possibility of life on another planet in another solar system, and maybe I can convince a biologically uninformed theorist to believe in my ridiculous theory if I claim I believe in their pseudoscientific nonsense and ignore what is currently known about how the epigenetic landscape is linked to the physical landscape of DNA in the organized genomes of all genera on this planet.
See also: Theorizing on H3.3 and Heterochromin in Aging
One principal carrier of epigenetic information is chromatin – a hierarchically organized complex of DNA, histones, and nonhistone proteins. Not surprisingly, the recent interest in ‘all things epigenetic’ begat new ideas on the role of chromatin in aging. It has been known since the 60s that DNA methylation is progressively lost with aging. Could epigenetic changes also irreversibly accumulate with time in BHL cells thus contributing to organismal, but not replicative, senescence?
The reason for my sarcasm (above) is the realization the evolutionary theorists and “big bang” cosmologists have been killing us with their ridiculous theories since the 60’s. If you were not taught to recognize the truth about cell type differentiation, you may never join the serious scientists who understand RNA-mediated events and who are Combating Evolution to Fight Disease.