Plant biology: You can’t make this stuff up.
By Mary Beth Aberlin | January 1, 2014
Excerpt: “Plants succeeded in dramatically expanding their genomes again and again through a process of chromosome-number multiplication called polyploidy, which usually begins with the joining of two diploid gametes that arise because of errors in cell division.”
My comment: Errors in cell division is a phrase that suggests mutations are somehow responsible for variation in the genome. In animals, nutrient-dependent pheromone-controlled amino acid substitutions are responsible for increasing organismal complexity. Thus, the real challenge may be to explain why plants and animals exhibit dramatic variation in genome size and complexity since the molecular mechanism of organismal complexity are probably the same. If so, the challenge can be placed into the context of ecological adaptations.
Use of animal models helped to eliminate theories about mutational burdens. Instead, it became clear that nutrient-dependent amino acid substitutions determine different cell types in different individuals of different species. Vitamins and minerals are as likely to biophysically constrain mutations and stabilize plant genomes as they are to stabilize animal genomes.
The metabolism of nutrients to species-specific chemical signals that control the physiology of reproduction may also modulate symbiotic interactions in the ecological niches of plants. If so, the ecological interactions of plants probably incorporate conserved molecular mechanisms of epigenetics in animals.
Nutrient-dependent ecological niche construction in plants may not result in what is commonly represented as chemically-controlled “social” niche construction of animals. However, it seems that others have realized that plants are social species, too. Thus, the epigenetic landscape probably becomes the physical landscape of plant DNA via nutrient-dependent chemically-controlled reproduction, which happens without mutations in the organized genomes of animal species.
You can make up theories about how plant biology works and try to make mutation-driven evolution fit the theories, but ultimately someone will be forced to look at conserved molecular mechanisms and biological facts.