Methylation maintains cell type differences (2)

By: James V. Kohl | Published on: March 31, 2015

Follow up to:  Methylation maintains cell type differences

Brain’s ‘gender’ may be quite flexible: Mechanism that plays key role in sexual differentiation of brain described

Excerpt: “Prof. McCarthy is now doing additional research on the links between the immune system and brain sex differences.”

See also: An immune hypothesis of sexual orientation

Excerpt: “…this ICS-hypothesis is consistent with the fact that many mfTSs can have children and does not preclude effects of odors and pheromones, but elucidates why those substances are less effective for individuals with sexual orientation altered by immune-mediated mechanisms. Importantly, Peeters et al. elegantly demonstrated that familial does not necessarily imply genetic (148). Their findings are relevant to immune-mediated alterations of SoGo because ± in the context of fetal and postnatal critical periods of immune development ± infections during pregnancy and/or early infancy might lastingly shape an individual’s sexually significant ICS.”
Excerpt from the 1996 review she co-authored: “Parenthetically it is interesting to note even the yeast Saccharomyces cerevisiae has a gene-based equivalent of sexual orientation (i.e., a-factor and alpha-factor physiologies). These differences arise from different epigenetic modifications of an otherwise identical MAT locus (Runge and Zakian, 1996; Wu and Haber, 1995).”

My comment (added to my comments at The Scientist):
RNA-directed DNA methylation links nutrient-dependent RNA-mediated cell type differentiation via amino acid substitutions in all cell types of all individuals of all genera via their physiology of reproduction. In species from microbes to man, cell type differentiation is nutrient-dependent and pheromone-controlled via fixation of the amino acid substitutions in the organized genome.
The human pheromone-deniers delayed the scientific progress on RNA-mediated cell type differentiation by at least two decades. During the same time they have delayed explanations of biologically-based cause and effect that link metabolic networks and genetic networks via the conserved molecular mechanisms of the biophysically constrained chemistry of protein folding.
What’s known has been detailed by others in the context of nutrigenomics and pharmacogenomics. It is great to see those who study sexual differentiation of the brain begin to catch up.
If someone asks why they did not know this, perhaps they will read Dobzhansky (1973) “…the so-called alpha chains of hemoglobin have identical sequences of amino acids in man and the chimpanzee, but they differ in a single amino acid (out of 141) in the gorilla” (p. 127).
See:  Pharmacogenomics at Mayo Clinic  (2.5 minutes) and Nutrient-dependent / Pheromone-controlled thermodynamics and thermoregulation (5.5 minutes)
2010 Powerpoint presentation 20 minutes International Society for Human Ethology
2007 Powerpoint presentation 45 minutes Society for the Scientific Study of Human Sexuality

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