Gene-expression memory in species from microbes to man

By: James V. Kohl | Published on: August 6, 2013

Short-term gene-expression ‘memory’ is inherited in proteins associated with DNA, new research finds August 6th, 2013 in Biology / Biotechnology
Article excerpt: “Bai explained that gene expression—the process by which certain genes are regulated or turned “on” or “off”—is one of the most fundamental processes in the life of any biological cell. Different programs of gene expression—even when cells have the same DNA—can lead to different cellular behavior and function. For example, even though a human muscle cell and a human nerve cell have identical DNA, they behave and function very differently. Misregulation of gene expression can affect cell fitness and lead to diseases. “Gene expression tends to vary from cell to cell,” Bai said. “Misregulation may happen in a small fraction of cells, and these cells may cause disease later on. Therefore it is important to study gene regulation at the single-cell level.””
My comment: I’m presenting a poster starting tomorrow during the ISHE Summer Institute in Ann Arbor, Michigan. The model I detail explains how nutrient-dependent gene regulation in species from microbes like yeast to man is controlled by the metabolism of the nutrients to species-specific pheromones that control reproduction. Nutrient stress and social stress cause gene-expression memory and may cause ‘misregulation’ of genes that is typically reported in the context of mutation-driven evolution.
For example, in our 1996 review we included a section on molecular epigenetics and the advent of sex differences in yeasts.
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).
This article extends what we detailed to what is currently known about sexual differentiation in mammals. See for example: Sex-specific differences in expression of histone demethylases Utx and Uty in mouse brain and neurons.
The molecular mechanisms for this sex specific differences are conserved in species from microbes to other mammals  (sans mutations). This suggests the molecular mechanisms can be included in a mammalian model that extends to humans (san mutations theory, via integration of what is currently neuoscientifically known. For comparison, what’s required from evolutionary theorists is a model of mutation-driven sex differences. Meanwhile, see Kondrashov (2012) for more information on how nutrient uptake leads to sex differences in yeast and to sex differences in pheromones that control reproduction in species from microbes to man.

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