Evolution at work sans random mutations

Evolution at work: Even yeast mothers sacrifice all for their babies

Excerpt:Mitochondria are the mini powerhouses of living cells, supplying the chemical energy all yeast and higher life forms need to survive. Like all cellular life, yeast need these structures to survive. In the new paper, the UCSF team describes how yeast cells ferry just the right amount of mitochondria along a network of protein tracks and molecular motors into the young yeastlings, which bud off their mother like mini-me’s.

From the article in Science: “Yeast cell size is known to respond to changes in metabolism brought about by nutritional environment (11), suggesting perhaps that a delay in mitochondrial inheritance somehow altered the cell’s metabolic state even though its environment remained unchanged.”

My comment: In my model, the phrase “from microbes to man” refers specifically to this yeast species, Saccharomyces cerevisiae (i.e., a microbe) where nutrient chemicals determine not only sexual orientation but also sexually dimorphic pheromone production as in all species due to the epigenetic effects of nutrient chemicals and their metabolism to pheromones that control reproduction.

Clearly, if I were to use a representation where yeast cells have mothers, I would be ridiculed in any attempt to convey the levels of biological complexity required to those who are unfamiliar with the basic principles of biology and levels of biological organization required to link sensory input directly to adaptive evolution in species from microbes to man (e.g., epigenetically). Thus, I am happy to see someone else attempt to use terminology that would otherwise be rejected — if only because those rejecting it understand nothing about the biological complexity of gene x environment interactions.

For a good explanation about the biological complexity that is involved see also: Commentary: Variation and Causation in the Environment and Genome. Unfortunately, this article gives the impression that less is known than has already been modeled in the context of the epigenetic effects of nutrition and pheromones and the microRNA / messenger RNA homeostasis that they control via intermolecular changes in DNA.

Author: James Kohl

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