ecological variation

RNA-mediated development

The Arthur M. Sackler Colloquia are sources for up-to-date information about biologically based cause and effect, which links epigenetic effects on hormones to the affects of hormones on behavior. The difference between effect and affect was place into the context here: Correction for McEwen, Brain on stress: How the social environment gets under the skin The authors note that on page 17184, right column, first paragraph, line 4, “effect” should instead appear as “affect.” In the early 1990’s, Bruce McEwen…

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Bees and primates automagically evolve

The Evolution of Social Bees Excerpt: …one key feature of increased sociality is an elaboration of gene regulation capacity. See also: From Fertilization to Adult Sexual Behavior (1996) Excerpt: …odor perception is more akin to the immune system workings where multitudes of receptors are each uniquely responsive to chemical structures (Bartoshuk and Beauchamp, 1994; Buck and Axel, 1991). Moreover, these receptor proteins are chemically and structurally similar to those that bind neurotransmitters and hormones (Buck and Axel, 1991). See also:…

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Chance mutations — not natural selection

A Surprise for Evolution in Giant Tree of Life Excerpt (with my emphasis): Each variant adapted to suit a different ecological niche. But Blair Hedges, a biologist at Temple University in Philadelphia, has proposed a provocative alternative: Adaptation had little to do with it. It was simply a matter of chance and time. See also: The Surprising Origins of Evolutionary Complexity July 16, 2013 Excerpt: Some argue that life has a built-in tendency to become more complex over time. Others…

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Viruses in gut microbes

Histone H3.3 is required for endogenous retroviral element silencing in embryonic stem cells 5/4/15 Excerpt: Extended Data Figure 3 | Generation of H3.3-isoform-specific antibodies. Related to Fig. 1. a, Schematic of amino acid sequence differences for the canonical histones H3.1 and H3.2 versus the histone variant H3.3. H3.3 differs from H3.2 or H3.1 at only 4 or 5 amino acids, positions 31, 87, 89, 90 and 96, as indicated. My comment: The difference in amino acid substitutions can be linked…

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MicroRNAs and the exposome

 MicroRNAs as Potential Signatures of Environmental Exposure or Effect: A Systematic Review Excerpt: Researchers are currently publishing extensive lists of miRNAs that are responsive to environmental exposures and showing their utility as biomarkers of effect. Future research should focus on identifying the molecular mechanism behind miRNA expression changes in response to exposure to determine whether the changes in miRNA expression are merely a symptom of the (patho)physiological processes the organism undergoes after exposure, or whether miRNAs are the drivers responsible…

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Thermodynamics and protein folding landscapes

The map of the body’s proteins Excerpt 1) Around half of our proteins are present in all of the body’s cells; these are known as ‘basic proteins’. Other proteins most commonly occur in one organ, but the researchers discovered that there are relatively few proteins which are unique to a certain tissue. Excerpt 2) ‘Our role in the project is above all linked to the medical and clinical aspects. Medical background knowledge is required to interpret what we see in…

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Feedback loops link insects to human brains

Ants Swarm Like Brains Think A neuroscientist studies ant colonies to understand feedback in the brain. By Carrie Arnold Illustration by Jonathon Rosen April 23, 2015 Excerpt 1: “The behavior of each individual in the group is set by the rate at which it meets other ants and a set of basic rules. Its behavior alters that of its neighbors, which in turn affects the original ant, in a classic example of feedback. The result is astonishing, complex behavior.” Excerpt…

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RNA Mediated

Life: conserved ion and amino acid transporters

The vital question: Why is life the way it is? Excerpt: “…any sufficiently advanced chemiosmotic geochemistry is indistinguishable from life.” My comment: If the differences between viruses and cellular life are removed, the link from viral microRNAs to the anti-entropic epigenetic effects of nutrient-dependent microRNAs limits explanations of how the nutrient-dependent microRNA/messenger RNA balance leads to the pheromone-controlled biodiversity of species from microbes to humans via RNA-mediated amino acid substitutions that differentiate all cell types in all individuals of all…

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Questions about life’s diversity

Questions about life can be answered in the context of what sustains it. 1) Answers must explain the diversity of life. 2) The diversity of life may help to explain the purpose of life. 3) Explaining the purpose of life may assist anyone who does not think they will live forever. 4) Answers to questions about life that explain life’s diversity must include what is known about the conserved molecular mechanisms that link differences in morphological and behavioral phenotypes in…

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RNA-directed gene choice

March 2015: ChemoSense; see Timothy S. McClintock: “Odorant Receptor Gene Choice” He concludes: “The epigenetic control of OR gene expression through repression and de-repression is a remarkable story, and as a fundamental mechanism intimately associated with the random differentiation of a neural progenitor cell into multiple neuronal subtypes, one wonders whether it might be a framework for understanding other instances of differentiation of neural subtypes (Lyons and Lomvardas, 2014).” My comment: The epigenetic control of OR gene expression is RNA-directed…

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