More complicated than 1-2-3

Genomic analysis of a key innovation in an experimental Escherichia coli population

Nature (2012)

Abstract excerpt: “Our findings illustrate the importance of promoter capture and altered gene regulation in mediating the exaptation events that often underlie evolutionary innovations.”

How Organisms Evolve New Functions: Evolution Is as Complicated as 1-2-3

Excerpt: “The actual mutation involved is quite complex. It re-arranged part of the bacteria’s DNA, making a new regulatory module that had not existed before. This new module causes the production of a protein that allows the bacteria to bring citrate into the cell when oxygen is present. ”

Excerpt: “It wasn’t a typical mutation at all, where just one base-pair, one letter, in the genome is changed,” he said. “Instead, part of the genome was copied so that two chunks of DNA were stitched together in a new way. One chunk encoded a protein to get citrate into the cell, and the other chunk caused that protein to be expressed.”

My comment: The evolution of the ability to use citrate occurs over generations of change, which means that nutrient chemical-dependent pheromone-controlled reproduction also occurs. This adds an important factor to their details of promoter capture and altered gene regulation in mediating the exaptation events.

The complexity of altered gene regulation must somehow be controlled across generations, which involves the transgenerational epigenetic effects of nutrient chemicals like the citrate. The use of a new nutrient chemical, for example, promotes an individual survival. For use of a new nutrient to promote species survival, the nutrient chemical must be metabolized to a species-specific pheromone that helps to controls the reproduction of  organisms as they evolve to better use the citrate molecule.

The problem here is that their concept of evolution via exaptation events and innovations is incompletely detailed. The level of complexity increases when the re-arranged DNA that makes a de novo regulatory module must somehow also lead to production of two different proteins.

One protein is a receptor protein that allows the nutrient chemical to enter the cell. The metabolism of that nutrient must then lead to production of another protein that controls reproduction by epigenetically enabling the production of another receptor for a species-specific chemical (i.e., a pheromone that controls reproduction). This complicates what has already been described as a complicated 1-2-3 process. A second-phase 1-2-3 process is required to control the reproduction of organisms that can evolve only if they do not starve to death.

If too many of them use too much of the available nutrient supply, the species becomes extinct. Extinction is an important factor to consider in the context of evolution. Isn’t it? Nutrient chemical use is altered by pheromones that control reproduction via quorum sensing, which is an important factor to consider in the context of mutations. It means you must have concurrent mutations that result from the epigenetic effect of a nutrient chemical that metabolizes to a pheromone that causes epigenetically controlled reproduction. Has anyone calculated the odds that two 1-2-3 stage dependent exaptation events would concurrently occur? That’s complicated


About James V. Kohl 1307 Articles
James Vaughn Kohl was the first to accurately conceptualize human pheromones, and began presenting his findings to the scientific community in 1992. He continues to present to, and publish for, diverse scientific and lay audiences, while constantly monitoring the scientific presses for new information that is relevant to the development of his initial and ongoing conceptualization of human pheromones. Recently, Kohl integrated scientific evidence that pinpoints the evolved neurophysiological mechanism that links olfactory/pheromonal input to genes in hormone-secreting cells of tissue in a specific area of the brain that is primarily involved in the sensory integration of olfactory and visual input, and in the development of human sexual preferences. His award-winning 2007 article/book chapter on multisensory integration: The Mind’s Eyes: Human pheromones, neuroscience, and male sexual preferences followed an award winning 2001 publication: Human pheromones: integrating neuroendocrinology and ethology, which was coauthored by disinguished researchers from Vienna. Rarely do researchers win awards in multiple disciplines, but Kohl’s 2001 award was for neuroscience, and his 2007 “Reiss Theory” award was for social science. Kohl has worked as a medical laboratory scientist since 1974, and he has devoted more than twenty-five years to researching the relationship between the sense of smell and the development of human sexual preferences. Unlike many researchers who work with non-human subjects, medical laboratory scientists use the latest technology from many scientific disciplines to perform a variety of specialized diagnostic medical testing on people. James V. Kohl is certified with: * American Society for Clinical Pathology * American Medical Technologists James V. Kohl is a member of: * Society for Neuroscience * Society for Behavioral Neuroendocrinology * Association for Chemoreception Sciences * Society for the Scientific Study of Sexuality * International Society for Human Ethology * American Society for Clinical Laboratory Science * Mensa, the international high IQ society