Yeast cells optimise their genomes in response to the environment
Excerpt:
The ability to sense environmental nutrient availability and act accordingly is a critical process for all organisms. Changing behaviour in response to nutrients can occur at many levels: the activity of proteins can be varied or new genes can be activated to produce a different set of proteins.
My comment: Could photic-zone eukaryotic plankton ribosomal diversity be linked from the light-induced de novo creation of amino acids to RNA-mediated gene duplication and the RNA-mediated amino acid substitutions that appear to differentiate all cell types of all individuals of all living genera via the physiology of their reproduction?
If so, this research report might link the speed of light on contact with water to nutrient-dependent pheromone-controlled RNA-mediated cell type differentiation at the advent of sexual reproduction in yeasts to sexual orientation in all species that sexually reproduce.
See for review: From Fertilization to Adult Sexual Behavior
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 (Saunders, Chue, Goebl, Craig, Clark, Powers, Eissenberg, Elgin, Rothfield, and Earnshaw, 1993; Singh, Miller, Pearce, Kothary, Burton, Paro, James, and Gaunt, 1991; Trofatter, Long, Murrell, Stotler, Gusella, and Buckler, 1995). Small intranuclear proteins also participate in generating alternative splicing techniques of pre-mRNA and, by this mechanism, contribute to sexual differentiation in at least two species, Drosophila melanogaster and Caenorhabditis elegans (Adler and Hajduk, 1994; de Bono, Zarkower, and Hodgkin, 1995; Ge, Zuo, and Manley, 1991; Green, 1991; Parkhurst and Meneely, 1994; Wilkins, 1995; Wolfner, 1988). That similar proteins perform functions in humans suggests the possibility that some human sex differences may arise from alternative splicings of otherwise identical genes.