Non-Genetic Inheritance and Changing Environments
Excerpt: “Until recently, biological information was thought to be transmitted across generations by DNA sequencing alone.”
My comment: Our 1996 review article in Hormones and Behavior included a section on molecular epigenetics that detailed what is required to get From Fertilization to Adult Sexual Behavior without focusing on DNA sequencing. That section made the role of pheromones perfectly clear in the context of nutrient-dependent hormone-organized and hormone-activated behaviors.
Our yeast-to-mammalian model was subsequently extended by others to invertebrates in Organizational and activational effects of hormones on insect behavior. Clearly, the conserved molecular mechanisms of cause and effect in species from microbes to man are responsible for the transmission of biological information across generations without changes in DNA sequencing. The required link from the epigenetic “landscape” to the physical landscape of DNA in the organized genomes of all species has since been thoroughly detailed with examples from model organisms such as nematodes, insects, other mammals, and humans.
Excerpt: “What are the molecular mechanisms for transducing parental environments into heritable epigenetic variation? Molecular (e.g., whole methylome analysis) and experimental (e.g., demethylating agents) advances have already begun to answer this question. DNA methylation is the most common, but certainly not the only, method of transgenerational information transfer [39]; others include chromatin states, histone modification, and prions [40]. But in most cases, just how the environmental signal (e.g., temperature) results in variation in methylation profiles is unknown.”
My comment: Temperature-dependent nutrient acquisition is clearly altered by changing local weather and climate changes. It is ridiculous to infer the link from the environment to variation in methylation profiles is unknown. The link is food! You cannot get to the required developmental differences in alternative splicings without it (in any species). See: Signaling Crosstalk: Integrating Nutrient Availability and Sex
If the local weather changes or the climate changes, food sources change. The metabolism of different foods to species-specific pheromones controls the physiology of reproduction. Thus, the transfer of biological information across generations is nutrient-dependent and pheromone-controlled. See, for example: Nutrient-dependent/pheromone-controlled adaptive evolution: a model.
Any claim that we don’t know how temperature-dependent environmental signals result in variation in methylation profiles should be viewed with suspicion. If these authors don’t know that methylation is thermodynamically altered at the cellular level to enable organism-level self-organization and nutrient-dependent reproduction controlled by pheromones, they should familiarize themselves with the extant literature on cause and effect via conserved molecular mechanisms in all species.
