Scientists complete the largest-ever comparative genomic study of birds.
December 11, 2014|
Excerpt: “Birds are model organisms for a number of human behaviors and conditions—For example, Jarvis compares vocal learning in birds and humans—so determining the genetic basis of such traits requires genetic history.”
My comment: Honeybees are model organisms for “…human immunity, disease resistance, allergic reaction, circadian rhythms, antibiotic resistance, the development of the brain and behavior, mental health, longevity, diseases of the X chromosome, learning and memory, as well as conditioned responses to sensory stimuli (Kohl, 2012). — cited in Nutrient-dependent/pheromone-controlled adaptive evolution: a model.
Taken together, what is currently known about nutrient-dependent cell type differentiation in the birds and the bees links the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man via the conserved molecular mechanisms of bio-physically constrained protein folding. For example, the metabolism of nutrients to species-specific pheromones controls fixation of nutrient-dependent amino acid substitutions that arise via RNA-directed DNA methylation and RNA-mediated events. The RNA-mediated events appear to differentiate all cell types of all organisms of all species.
In vertebrates, different forms of gonadotropin releasing hormone (GnRH) and its receptors link coelacanths to birds without the pseudoscientific nonsense of claims that birds evolved from dinosaurs during the past ~ 65 million years. Simply put, there appears to be no difference in the molecular mechanisms of protein folding that link nutrient-dependent amino acid substitutions from the thermodynamic cycles of protein biosynthesis and degradation to cell type differentiation and the morphological and behavioral phenotypes of all species.
“More and more, we’re realizing that folding is regulation,” said study co-first author Suhas Rao… When you see genes turn on or off, what lies behind that is a change in folding. It’s a different way of thinking about how cells work.”
If you’re a serious scientist, changes in protein folding that differentiate cell types is the only way of thinking about how cells work. Mutations perturb protein folding, which means they are not beneficial.That’s why olfaction and pheromones are important to think about.
Pseudoscientists used to think that birds and humans were microsmatic, until serious scientists showed that the physiology of reproduction in birds is nutrient-dependent and pheromone-controlled. See for example: Estrogen receptor α polymorphism in a species with alternative behavioral phenotypes for the role of nutrient-dependent pheromone-controlled amino acid substitutions in white-throated sparrows. Still, there are a few seemingly serious scientists are among those who make such ridiculous claims about humans. See for example: Introduction to the special issue on Chemosignals and Reproduction
“The issue of human ‘pheromones’ is a controversial topic and the authors successfully balance competing perspectives.However, it is fair to say that, on balance, social odors play a much more subtle and much less critical role in human reproduction when compared to other mammals.” — Aras Petrulis
My comment: Nutrient-dependent pheromone-controlled cell type differentiation plays the most critical role in human reproduction and in reproduction in all species from microbes to man. The above claim has been repeatedly made by those who appear to have learned nothing about molecular epigenetics and RNA-mediated events since we first detailed them in our 1996 Hormones and Behavior review: From Fertilization to Adult Sexual Behavior.
We didn’t include all species because not enough was known about RNA-mediated cell type differences. But we didn’t exclude any species for the same reason. Since there was no experimental evidence that linked mutations and natural selection to the evolution of biodiversity, it made sense to model cell type differentiation based on what was known and predict that the model could be extended across species, as it has been during the past 18 years. See: Organizational and activational effects of hormones on insect behavior and Honey bees as a model for understanding mechanisms of life history transitions.