Pheromones and multicellularity
August 17, 2012 | James Kohl
A single-celled relative of animals forms colonies when exposed to a bacterial product, hinting at the possible origins of multicellularity. By Hayley Dunning | August 15, 2012
Excerpted from the article: “Who would have guessed a molecule like that could be involved in colonization?”
In Kohl (2012) I wrote that reproduction began with an active nutrient uptake mechanism in heterospecifics and that the mechanism evolved to become symbiogenesis in the conspecifics of asexual organisms, citing Margulis (1998). My speculation was based on the fact that nutrient chemicals are required for individual survival and the fact that metabolism of the nutrient chemical to pheromones controls reproduction via the molecular biology of intracellular signaling and stochastic gene expression, which is common to all species. The common molecular biology makes it clear that integrated chemical ecology (i.e., the epigenetic effects of nutrient chemicals and pheromones on gene expresssion) is required for adaptive evolution (e.g., via ecological, social, neurogenic, and socio-cognitive niche construction.)
The authors of this article make it clear to me that chemical signals akin to species-specific pheromones are responsible for the ligand-receptor binding that enables the progression to colony formation as a more effective means of nutrient acquisition. This must occur at the same time that quorum sensing ensures the supply of nutrients is not exhausted. Thus, the symbiotic relationship is maintained, which at least partially explains why one organism might produce a species-specific ‘pheromone’ that promoted it species’ survival via a signal of what’s for dinner to a heterospecific diner. Simply put, that conceptualization seems to be only a matter of pattern recognition in what would otherwise literally be a dog-eat-dog world. Species invariably prefer to eat heterospecifics and avoid cannibalism as a built-in requirement for adaptive evolution.